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PSYC 210: Foundations of Psychology

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What is a literature review?

Conducting a literature review, organizing a literature review, writing a literature review, helpful book.

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A  literature review  is a compilation of the works published in a particular field of study or line of research, usually over a specific period of time, in the form of an in-depth, critical bibliographic essay or annotated list in which attention is drawn to the most significant works.

• Summarizes and analyzes previous research relevant to a topic
• Includes scholarly books and articles published in academic journals
• Can be an specific scholarly paper or a section in a research paper

The objective of a Literature Review is to find previous published scholarly works relevant to an specific topic

• Help gather ideas or information
• Keep up to date in current trends and findings
• Help develop new questions

A literature review is important because it:

• Explains the background of research on a topic
• Demonstrates why a topic is significant to a subject area
• Helps focus your own research questions or problems
• Discovers relationships between research studies/ideas
• Suggests unexplored ideas or populations
• Identifies major themes, concepts, and researchers on a topic
• Tests assumptions; may help counter preconceived ideas and remove unconscious bias
• Identifies critical gaps, points of disagreement, or potentially flawed methodology or theoretical approaches

Source: "What is a Literature Review?", Old Dominion University,  https://guides.lib.odu.edu/c.php?g=966167&p=6980532

1. Choose a topic. Define your research question. 

Your literature review should be guided by a central research question. It represents background and research developments related to a specific research question, interpreted, and analyzed by you in a synthesized way. 

• Make sure your research question is not too broad or too narrow.
• Write down terms that are related to your question for they will be useful for searches later. 

2. Decide on the scope of your review. 

How many studies do you need to look at? How comprehensive should it be? How many years should it cover? 

• This may depend on your assignment.
• Consider these things when planning your time for research. 

3. Select the databases you will use to conduct your searches. 

• By Research Guide 

4. Conduct your searches and find the literature. 

• Review the abstracts carefully - this will save you time!
• Many databases will have a search history tab for you to return to for later.
• Use bibliographies and references of research studies to locate others.
• Use citation management software such as Zotero to keep track of your research citations. 

5. Review the literature. 

Some questions to help you analyze the research: 

• What was the research question you are reviewing? What are the authors trying to discover? 
• Was the research funded by a source that could influence the findings? 
• What were the research methodologies? Analyze the literature review, samples and variables used, results, and conclusions. Does the research seem complete? Could it have been conducted more soundly? What further questions does it raise? 
• If there are conflicted studies, why do you think that is? 
• How are the authors viewed in the field? Are they experts or novices? Has the study been cited? 

Source: "Literature Review", University of West Florida,  https://libguides.uwf.edu/c.php?g=215113&p=5139469

A literature review is not a summary of the sources but a synthesis of the sources. It is made up of the topics the sources are discussing. Each section of the review is focused on a topic, and the relevant sources are discussed within the context of that topic. 

1. Select the most relevant material from the sources

• Could be material that answers the question directly
• Extract as a direct quote or paraphrase 

2. Arrange that material so you can focus on it apart from the source text itself

• You are now working with fewer words/passages
• Material is all in one place

3. Group similar points, themes, or topics together and label them 

• The labels describe the points, themes, or topics that are the backbone of your paper’s structure

4. Order those points, themes, or topics as you will discuss them in the paper, and turn the labels into actual assertions

• A sentence that makes a point that is directly related to your research question or thesis 

This is now the outline for your literature review. 

Source: "Organizing a Review of the Literature – The Basics", George Mason University Writing Center,  https://writingcenter.gmu.edu/writing-resources/research-based-writing/organizing-literature-reviews-the-basics

• Literature Review Matrix Here is a template on how people tend to organize their thoughts. The matrix template is a good way to write out the key parts of each article and take notes. Downloads as an XLSX file.

The most common way that literature reviews are organized is by theme or author. Find a general pattern of structure for the review. When organizing the review, consider the following: 

• the methodology 
• the quality of the findings or conclusions
• major strengths and weaknesses
• any other important information

Writing Tips: 

• Be selective - Select only the most important points in each source to highlight in the review. It should directly relate to the review's focus.
• Use quotes sparingly.
• Keep your own voice - Your voice (the writer's) should remain front and center. .   
• Aim for one key figure/table per section to illustrate complex content, summarize a large body of relevant data, or describe the order of a process
• Legend below image/figure and above table and always refer to them in text 

Source: "Composing your Literature Review", Florida A&M University,  https://library.famu.edu/c.php?g=577356&p=3982811

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• Literature Review Guidelines

Making sense of what has been written on your topic.

Goals of a literature review:.

Before doing work in primary sources, historians must know what has been written on their topic.  They must be familiar with theories and arguments–as well as facts–that appear in secondary sources.

Before you proceed with your research project, you too must be familiar with the literature: you do not want to waste time on theories that others have disproved and you want to take full advantage of what others have argued.  You want to be able to discuss and analyze your topic.

Your literature review will demonstrate your familiarity with your topic’s secondary literature.

GUIDELINES FOR A LITERATURE REVIEW:

1) LENGTH:  8-10 pages of text for Senior Theses (485) (consult with your professor for other classes), with either footnotes or endnotes and with a works-consulted bibliography. [See also the  citation guide  on this site.]

2) NUMBER OF WORKS REVIEWED: Depends on the assignment, but for Senior Theses (485), at least ten is typical.

3) CHOOSING WORKS:

Your literature review must include enough works to provide evidence of both the breadth and the depth of the research on your topic or, at least, one important angle of it.  The number of works necessary to do this will depend on your topic. For most topics, AT LEAST TEN works (mostly books but also significant scholarly articles) are necessary, although you will not necessarily give all of them equal treatment in your paper (e.g., some might appear in notes rather than the essay). 4) ORGANIZING/ARRANGING THE LITERATURE:

As you uncover the literature (i.e., secondary writing) on your topic, you should determine how the various pieces relate to each other.  Your ability to do so will demonstrate your understanding of the evolution of literature.

You might determine that the literature makes sense when divided by time period, by methodology, by sources, by discipline, by thematic focus, by race, ethnicity, and/or gender of author, or by political ideology.  This list is not exhaustive.  You might also decide to subdivide categories based on other criteria.  There is no “rule” on divisions—historians wrote the literature without consulting each other and without regard to the goal of fitting into a neat, obvious organization useful to students.

The key step is to FIGURE OUT the most logical, clarifying angle.  Do not arbitrarily choose a categorization; use the one that the literature seems to fall into.  How do you do that?  For every source, you should note its thesis, date, author background, methodology, and sources.  Does a pattern appear when you consider such information from each of your sources?  If so, you have a possible thesis about the literature.  If not, you might still have a thesis.

Consider: Are there missing elements in the literature?  For example, no works published during a particular (usually fairly lengthy) time period?  Or do studies appear after long neglect of a topic?  Do interpretations change at some point?  Does the major methodology being used change?  Do interpretations vary based on sources used?

Follow these links for more help on analyzing  historiography  and  historical perspective .

5) CONTENTS OF LITERATURE REVIEW:

The literature review is a research paper with three ingredients:

a) A brief discussion of the issue (the person, event, idea). [While this section should be brief, it needs to set up the thesis and literature that follow.] b) Your thesis about the literature c) A clear argument, using the works on topic as evidence, i.e., you discuss the sources in relation to your thesis, not as a separate topic.

These ingredients must be presented in an essay with an introduction, body, and conclusion.

6) ARGUING YOUR THESIS:

The thesis of a literature review should not only describe how the literature has evolved, but also provide a clear evaluation of that literature.  You should assess the literature in terms of the quality of either individual works or categories of works.  For instance, you might argue that a certain approach (e.g. social history, cultural history, or another) is better because it deals with a more complex view of the issue or because they use a wider array of source materials more effectively. You should also ensure that you integrate that evaluation throughout your argument.  Doing so might include negative assessments of some works in order to reinforce your argument regarding the positive qualities of other works and approaches to the topic.

Within each group, you should provide essential information about each work: the author’s thesis, the work’s title and date, the author’s supporting arguments and major evidence.

In most cases, arranging the sources chronologically by publication date within each section makes the most sense because earlier works influenced later ones in one way or another.  Reference to publication date also indicates that you are aware of this significant historiographical element.

As you discuss each work, DO NOT FORGET WHY YOU ARE DISCUSSING IT.  YOU ARE PRESENTING AND SUPPORTING A THESIS ABOUT THE LITERATURE.

When discussing a particular work for the first time, you should refer to it by the author’s full name, the work’s title, and year of publication (either in parentheses after the title or worked into the sentence).

For example, “The field of slavery studies has recently been transformed by Ben Johnson’s The New Slave (2001)” and “Joe Doe argues in his 1997 study, Slavery in America, that . . . .”

Your paper should always note secondary sources’ relationship to each other, particularly in terms of your thesis about the literature (e.g., “Unlike Smith’s work, Mary Brown’s analysis reaches the conclusion that . . . .” and “Because of Anderson’s reliance on the president’s personal papers, his interpretation differs from Barry’s”). The various pieces of the literature are “related” to each other, so you need to indicate to the reader some of that relationship.  (It helps the reader follow your thesis, and it convinces the reader that you know what you are talking about.)

7) DOCUMENTATION:

Each source you discuss in your paper must be documented using footnotes/endnotes and a bibliography.  Providing author and title and date in the paper is not sufficient.  Use correct Turabian/Chicago Manual of Style form.  [See  Bibliography  and  Footnotes/Endnotes  pages.]

In addition, further supporting, but less significant, sources should be included in  content foot or endnotes .  (e.g., “For a similar argument to Ben Johnson’s, see John Terry, The Slave Who Was New (New York: W. W. Norton, 1985), 3-45.”)

8 ) CONCLUSION OF LITERATURE REVIEW:

Your conclusion should not only reiterate your argument (thesis), but also discuss questions that remain unanswered by the literature.  What has the literature accomplished?  What has not been studied?  What debates need to be settled?

Additional writing guidelines

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Under recognized yet a clinically relevant impact of aneurysm location in Distal Anterior Cerebral Artery (DACA) aneurysms: insights from a contemporary surgical experience

• Published: 31 August 2024
• Volume 47 , article number  517 , ( 2024 )

Cite this article

• Abhishek Halder 1 ,
• Kuntal Kanti Das 1 ,
• Soumen Kanjilal 1 ,
• Kamlesh Singh Bhaisora 1 ,
• Ashutosh Kumar 1 ,
• Pawan Kumar Verma 1 ,
• Ved Prakash Maurya 1 ,
• Anant Mehrotra 1 ,
• Arun Kumar Srivastava 1 &
• Awadhesh Kumar Jaiswal 1  

Aneurysms of the distal anterior cerebral artery (DACA) are rare but surgically challenging. Despite a known therapeutic implication of the aneurysm location on the DACA territory, the literature is unclear about its clinical and prognostic significance. Our surgical experience over the last 5 years was reviewed to compare the clinical, operative, and outcome characteristics between aneurysms located below the mid portion of the genu of the corpus callosum (called proximal aneurysms) to those distal to this point (called distal aneurysms). A prognostic factor analysis was done using uni and multivariable analysis. A total of 34 patients were treated (M: F = 1:2.3). The distal group had a higher frequency of poor clinical grade at presentation ( n  = 9, 47.4%) in contrast to ( n  = 2, 13.3%) proximal aneurysms ( p  = 0.039). Despite an overall tendency for a delayed functional improvement in these patients, the results were mainly due to favorable outcomes in the proximal group (favourable functional outcomes at discharge and at last follow-up being 80% and 86.7% respectively). On the multivariable analysis, only WFNS grade (> 2) at presentation (OR = 13.75; 95CI = 1.2–157.7) ( p  = 0.035) and application of temporary clips (AOR = 34.32; 95CI = 2.59–454.1) ( p  = 0.007), both of which were more in the distal group, independently predicted a poor long term functional outcome. Thus, the aneurysm location impacts the preoperative clinical grade, the intraoperative aneurysm rupture risk rate as well as the temporary clipping requirement. A combination of these factors leads to worse short and long-term functional outcomes in the distal DACA aneurysms.

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Data availability

The data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the corresponding author upon reasonable request. Data are located in controlled access data storage at the institute were the study was conducted.

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The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

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Department of Neurosurgery, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, UP 226014, India

Abhishek Halder, Kuntal Kanti Das, Soumen Kanjilal, Kamlesh Singh Bhaisora, Ashutosh Kumar, Pawan Kumar Verma, Ved Prakash Maurya, Anant Mehrotra, Arun Kumar Srivastava & Awadhesh Kumar Jaiswal

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Contributions

Conceptualization - AH, KKD, SK; Methodology - AH, KKD, SK, KSB; Formal analysis and investigation - AH, KKD, SK and AK; Writing – original draft - AH, KKD, SK and AM; Writing - review & editing - AH, KKD, SK, KSB, PKV and AKS; Resources - AH, KKD, SK, VPM and PKV; Supervision - KKD, AM, AKS and AKJ;

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Correspondence to Kuntal Kanti Das .

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This is an observational study. The Institutional Ethics Committee has confirmed that no ethical approval is required.

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As this a retrospective study, the patients’ consent to participate were waived off by the Institutional Ethics Committee.

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The manuscript does not contain any information from which a patient’s identity could be disclosed.

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Halder, A., Das, K.K., Kanjilal, S. et al. Under recognized yet a clinically relevant impact of aneurysm location in Distal Anterior Cerebral Artery (DACA) aneurysms: insights from a contemporary surgical experience. Neurosurg Rev 47 , 517 (2024). https://doi.org/10.1007/s10143-024-02759-5

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Received : 07 March 2024

Revised : 28 June 2024

Accepted : 23 August 2024

Published : 31 August 2024

DOI : https://doi.org/10.1007/s10143-024-02759-5

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• Published: 26 August 2024

Learning effect of online versus onsite education in health and medical scholarship – protocol for a cluster randomized trial

• Rie Raffing 1 ,
• Lars Konge 2 &
• Hanne Tønnesen 1  

BMC Medical Education volume  24 , Article number:  927 ( 2024 ) Cite this article

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The disruption of health and medical education by the COVID-19 pandemic made educators question the effect of online setting on students’ learning, motivation, self-efficacy and preference. In light of the health care staff shortage online scalable education seemed relevant. Reviews on the effect of online medical education called for high quality RCTs, which are increasingly relevant with rapid technological development and widespread adaption of online learning in universities. The objective of this trial is to compare standardized and feasible outcomes of an online and an onsite setting of a research course regarding the efficacy for PhD students within health and medical sciences: Primarily on learning of research methodology and secondly on preference, motivation, self-efficacy on short term and academic achievements on long term. Based on the authors experience with conducting courses during the pandemic, the hypothesis is that student preferred onsite setting is different to online setting.

Cluster randomized trial with two parallel groups. Two PhD research training courses at the University of Copenhagen are randomized to online (Zoom) or onsite (The Parker Institute, Denmark) setting. Enrolled students are invited to participate in the study. Primary outcome is short term learning. Secondary outcomes are short term preference, motivation, self-efficacy, and long-term academic achievements. Standardized, reproducible and feasible outcomes will be measured by tailor made multiple choice questionnaires, evaluation survey, frequently used Intrinsic Motivation Inventory, Single Item Self-Efficacy Question, and Google Scholar publication data. Sample size is calculated to 20 clusters and courses are randomized by a computer random number generator. Statistical analyses will be performed blinded by an external statistical expert.

Primary outcome and secondary significant outcomes will be compared and contrasted with relevant literature. Limitations include geographical setting; bias include lack of blinding and strengths are robust assessment methods in a well-established conceptual framework. Generalizability to PhD education in other disciplines is high. Results of this study will both have implications for students and educators involved in research training courses in health and medical education and for the patients who ultimately benefits from this training.

Trial registration

Retrospectively registered at ClinicalTrials.gov: NCT05736627. SPIRIT guidelines are followed.

Peer Review reports

Medical education was utterly disrupted for two years by the COVID-19 pandemic. In the midst of rearranging courses and adapting to online platforms we, with lecturers and course managers around the globe, wondered what the conversion to online setting did to students’ learning, motivation and self-efficacy [ 1 , 2 , 3 ]. What the long-term consequences would be [ 4 ] and if scalable online medical education should play a greater role in the future [ 5 ] seemed relevant and appealing questions in a time when health care professionals are in demand. Our experience of performing research training during the pandemic was that although PhD students were grateful for courses being available, they found it difficult to concentrate related to the long screen hours. We sensed that most students preferred an onsite setting and perceived online courses a temporary and inferior necessity. The question is if this impacted their learning?

Since the common use of the internet in medical education, systematic reviews have sought to answer if there is a difference in learning effect when taught online compared to onsite. Although authors conclude that online learning may be equivalent to onsite in effect, they agree that studies are heterogeneous and small [ 6 , 7 ], with low quality of the evidence [ 8 , 9 ]. They therefore call for more robust and adequately powered high-quality RCTs to confirm their findings and suggest that students’ preferences in online learning should be investigated [ 7 , 8 , 9 ].

This uncovers two knowledge gaps: I) High-quality RCTs on online versus onsite learning in health and medical education and II) Studies on students’ preferences in online learning.

Recently solid RCTs have been performed on the topic of web-based theoretical learning of research methods among health professionals [ 10 , 11 ]. However, these studies are on asynchronous courses among medical or master students with short term outcomes.

This uncovers three additional knowledge gaps: III) Studies on synchronous online learning IV) among PhD students of health and medical education V) with long term measurement of outcomes.

The rapid technological development including artificial intelligence (AI) and widespread adaption as well as application of online learning forced by the pandemic, has made online learning well-established. It represents high resolution live synchronic settings which is available on a variety of platforms with integrated AI and options for interaction with and among students, chat and break out rooms, and exterior digital tools for teachers [ 12 , 13 , 14 ]. Thus, investigating online learning today may be quite different than before the pandemic. On one hand, it could seem plausible that this technological development would make a difference in favour of online learning which could not be found in previous reviews of the evidence. On the other hand, the personal face-to-face interaction during onsite learning may still be more beneficial for the learning process and combined with our experience of students finding it difficult to concentrate when online during the pandemic we hypothesize that outcomes of the onsite setting are different from the online setting.

To support a robust study, we design it as a cluster randomized trial. Moreover, we use the well-established and widely used Kirkpatrick’s conceptual framework for evaluating learning as a lens to assess our outcomes [ 15 ]. Thus, to fill the above-mentioned knowledge gaps, the objective of this trial is to compare a synchronous online and an in-person onsite setting of a research course regarding the efficacy for PhD students within the health and medical sciences:

Primarily on theoretical learning of research methodology and

Secondly on

◦ Preference, motivation, self-efficacy on short term

◦ Academic achievements on long term

Trial design

This study protocol covers synchronous online and in-person onsite setting of research courses testing the efficacy for PhD students. It is a two parallel arms cluster randomized trial (Fig.  1 ).

Consort flow diagram

The study measures baseline and post intervention. Baseline variables and knowledge scores are obtained at the first day of the course, post intervention measurement is obtained the last day of the course (short term) and monthly for 24 months (long term).

Randomization is stratified giving 1:1 allocation ratio of the courses. As the number of participants within each course might differ, the allocation ratio of participants in the study will not fully be equal and 1:1 balanced.

Study setting

The study site is The Parker Institute at Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Denmark. From here the courses are organized and run online and onsite. The course programs and time schedules, the learning objective, the course management, the lecturers, and the delivery are identical in the two settings. The teachers use the same introductory presentations followed by training in break out groups, feed-back and discussions. For the online group, the setting is organized as meetings in the online collaboration tool Zoom® [ 16 ] using the basic available technicalities such as screen sharing, chat function for comments, and breakout rooms and other basics digital tools if preferred. The online version of the course is synchronous with live education and interaction. For the onsite group, the setting is the physical classroom at the learning facilities at the Parker Institute. Coffee and tea as well as simple sandwiches and bottles of water, which facilitate sociality, are available at the onsite setting. The participants in the online setting must get their food and drink by themselves, but online sociality is made possible by not closing down the online room during the breaks. The research methodology courses included in the study are “Practical Course in Systematic Review Technique in Clinical Research”, (see course programme in appendix 1) and “Getting started: Writing your first manuscript for publication” [ 17 ] (see course programme in appendix 2). The two courses both have 12 seats and last either three or three and a half days resulting in 2.2 and 2.6 ECTS credits, respectively. They are offered by the PhD School of the Faculty of Health and Medical Sciences, University of Copenhagen. Both courses are available and covered by the annual tuition fee for all PhD students enrolled at a Danish university.

Eligibility criteria

Inclusion criteria for participants: All PhD students enrolled on the PhD courses participate after informed consent: “Practical Course in Systematic Review Technique in Clinical Research” and “Getting started: Writing your first manuscript for publication” at the PhD School of the Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.

Exclusion criteria for participants: Declining to participate and withdrawal of informed consent.

Informed consent

The PhD students at the PhD School at the Faculty of Health Sciences, University of Copenhagen participate after informed consent, taken by the daily project leader, allowing evaluation data from the course to be used after pseudo-anonymization in the project. They are informed in a welcome letter approximately three weeks prior to the course and again in the introduction the first course day. They register their consent on the first course day (Appendix 3). Declining to participate in the project does not influence their participation in the course.

Interventions

Online course settings will be compared to onsite course settings. We test if the onsite setting is different to online. Online learning is increasing but onsite learning is still the preferred educational setting in a medical context. In this case onsite learning represents “usual care”. The online course setting is meetings in Zoom using the technicalities available such as chat and breakout rooms. The onsite setting is the learning facilities, at the Parker Institute, Bispebjerg and Frederiksberg Hospital, The Capital Region, University of Copenhagen, Denmark.

The course settings are not expected to harm the participants, but should a request be made to discontinue the course or change setting this will be met, and the participant taken out of the study. Course participants are allowed to take part in relevant concomitant courses or other interventions during the trial.

Strategies to improve adherence to interventions

Course participants are motivated to complete the course irrespectively of the setting because it bears ECTS-points for their PhD education and adds to the mandatory number of ECTS-points. Thus, we expect adherence to be the same in both groups. However, we monitor their presence in the course and allocate time during class for testing the short-term outcomes ( motivation, self-efficacy, preference and learning). We encourage and, if necessary, repeatedly remind them to register with Google Scholar for our testing of the long-term outcome (academic achievement).

Outcomes are related to the Kirkpatrick model for evaluating learning (Fig.  2 ) which divides outcomes into four different levels; Reaction which includes for example motivation, self-efficacy and preferences, Learning which includes knowledge acquisition, Behaviour for practical application of skills when back at the job (not included in our outcomes), and Results for impact for end-users which includes for example academic achievements in the form of scientific articles [ 18 , 19 , 20 ].

The Kirkpatrick model

Primary outcome

The primary outcome is short term learning (Kirkpatrick level 2).

Learning is assessed by a Multiple-Choice Questionnaire (MCQ) developed prior to the RCT specifically for this setting (Appendix 4). First the lecturers of the two courses were contacted and asked to provide five multiple choice questions presented as a stem with three answer options; one correct answer and two distractors. The questions should be related to core elements of their teaching under the heading of research training. The questions were set up to test the cognition of the students at the levels of "Knows" or "Knows how" according to Miller's Pyramid of Competence and not their behaviour [ 21 ]. Six of the course lecturers responded and out of this material all the questions which covered curriculum of both courses were selected. It was tested on 10 PhD students and within the lecturer group, revised after an item analysis and English language revised. The MCQ ended up containing 25 questions. The MCQ is filled in at baseline and repeated at the end of the course. The primary outcomes based on the MCQ is estimated as the score of learning calculated as number of correct answers out of 25 after the course. A decrease of points of the MCQ in the intervention groups denotes a deterioration of learning. In the MCQ the minimum score is 0 and 25 is maximum, where 19 indicates passing the course.

Furthermore, as secondary outcome, this outcome measurement will be categorized as binary outcome to determine passed/failed of the course defined by 75% (19/25) correct answers.

The learning score will be computed on group and individual level and compared regarding continued outcomes by the Mann–Whitney test comparing the learning score of the online and onsite groups. Regarding the binomial outcome of learning (passed/failed) data will be analysed by the Fisher’s exact test on an intention-to-treat basis between the online and onsite. The results will be presented as median and range and as mean and standard deviations, for possible future use in meta-analyses.

Secondary outcomes

Motivation assessment post course: Motivation level is measured by the Intrinsic Motivation Inventory (IMI) Scale [ 22 ] (Appendix 5). The IMI items were randomized by random.org on the 4th of August 2022. It contains 12 items to be assessed by the students on a 7-point Likert scale where 1 is “Not at all true”, 4 is “Somewhat true” and 7 is “Very true”. The motivation score will be computed on group and individual level and will then be tested by the Mann–Whitney of the online and onsite group.

Self-efficacy assessment post course: Self-efficacy level is measured by a single-item measure developed and validated by Williams and Smith [ 23 ] (Appendix 6). It is assessed by the students on a scale from 1–10 where 1 is “Strongly disagree” and 10 is “Strongly agree”. The self-efficacy score will be computed on group and individual level and tested by a Mann–Whitney test to compare the self-efficacy score of the online and onsite group.

Preference assessment post course: Preference is measured as part of the general course satisfaction evaluation with the question “If you had the option to choose, which form would you prefer this course to have?” with the options “onsite form” and “online form”.

Academic achievement assessment is based on 24 monthly measurements post course of number of publications, number of citations, h-index, i10-index. This data is collected through the Google Scholar Profiles [ 24 ] of the students as this database covers most scientific journals. Associations between onsite/online and long-term academic will be examined with Kaplan Meyer and log rank test with a significance level of 0.05.

Participant timeline

Enrolment for the course at the Faculty of Health Sciences, University of Copenhagen, Denmark, becomes available when it is published in the course catalogue. In the course description the course location is “To be announced”. Approximately 3–4 weeks before the course begins, the participant list is finalized, and students receive a welcome letter containing course details, including their allocation to either the online or onsite setting. On the first day of the course, oral information is provided, and participants provide informed consent, baseline variables, and base line knowledge scores.

The last day of scheduled activities the following scores are collected, knowledge, motivation, self-efficacy, setting preference, and academic achievement. To track students' long term academic achievements, follow-ups are conducted monthly for a period of 24 months, with assessments occurring within one week of the last course day (Table  1 ).

Sample size

The power calculation is based on the main outcome, theoretical learning on short term. For the sample size determination, we considered 12 available seats for participants in each course. To achieve statistical power, we aimed for 8 clusters in both online and onsite arms (in total 16 clusters) to detect an increase in learning outcome of 20% (learning outcome increase of 5 points). We considered an intraclass correlation coefficient of 0.02, a standard deviation of 10, a power of 80%, and a two-sided alpha level of 5%. The Allocation Ratio was set at 1, implying an equal number of subjects in both online and onsite group.

Considering a dropout up to 2 students per course, equivalent to 17%, we determined that a total of 112 participants would be needed. This calculation factored in 10 clusters of 12 participants per study arm, which we deemed sufficient to assess any changes in learning outcome.

The sample size was estimated using the function n4means from the R package CRTSize [ 25 ].

Recruitment

Participants are PhD students enrolled in 10 courses of “Practical Course in Systematic Review Technique in Clinical Research” and 10 courses of “Getting started: Writing your first manuscript for publication” at the PhD School of the Faculty of Health Sciences, University of Copenhagen, Denmark.

Assignment of interventions: allocation

Randomization will be performed on course-level. The courses are randomized by a computer random number generator [ 26 ]. To get a balanced randomization per year, 2 sets with 2 unique random integers in each, taken from the 1–4 range is requested.

The setting is not included in the course catalogue of the PhD School and thus allocation to online or onsite is concealed until 3–4 weeks before course commencement when a welcome letter with course information including allocation to online or onsite setting is distributed to the students. The lecturers are also informed of the course setting at this time point. If students withdraw from the course after being informed of the setting, a letter is sent to them enquiring of the reason for withdrawal and reason is recorded (Appendix 7).

The allocation sequence is generated by a computer random number generator (random.org). The participants and the lecturers sign up for the course without knowing the course setting (online or onsite) until 3–4 weeks before the course.

Assignment of interventions: blinding

Due to the nature of the study, it is not possible to blind trial participants or lecturers. The outcomes are reported by the participants directly in an online form, thus being blinded for the outcome assessor, but not for the individual participant. The data collection for the long-term follow-up regarding academic achievements is conducted without blinding. However, the external researcher analysing the data will be blinded.

Data collection and management

Data will be collected by the project leader (Table  1 ). Baseline variables and post course knowledge, motivation, and self-efficacy are self-reported through questionnaires in SurveyXact® [ 27 ]. Academic achievements are collected through Google Scholar profiles of the participants.

Given that we are using participant assessments and evaluations for research purposes, all data collection – except for monthly follow-up of academic achievements after the course – takes place either in the immediate beginning or ending of the course and therefore we expect participant retention to be high.

Data will be downloaded from SurveyXact and stored in a locked and logged drive on a computer belonging to the Capital Region of Denmark. Only the project leader has access to the data.

This project conduct is following the Danish Data Protection Agency guidelines of the European GDPR throughout the trial. Following the end of the trial, data will be stored at the Danish National Data Archive which fulfil Danish and European guidelines for data protection and management.

Statistical methods

Data is anonymized and blinded before the analyses. Analyses are performed by a researcher not otherwise involved in the inclusion or randomization, data collection or handling. All statistical tests will be testing the null hypotheses assuming the two arms of the trial being equal based on corresponding estimates. Analysis of primary outcome on short-term learning will be started once all data has been collected for all individuals in the last included course. Analyses of long-term academic achievement will be started at end of follow-up.

Baseline characteristics including both course- and individual level information will be presented. Table 2 presents the available data on baseline.

We will use multivariate analysis for identification of the most important predictors (motivation, self-efficacy, sex, educational background, and knowledge) for best effect on short and long term. The results will be presented as risk ratio (RR) with 95% confidence interval (CI). The results will be considered significant if CI does not include the value one.

All data processing and analyses were conducted using R statistical software version 4.1.0, 2021–05-18 (R Foundation for Statistical Computing, Vienna, Austria).

If possible, all analysis will be performed for “Practical Course in Systematic Review Technique in Clinical Research” and for “Getting started: Writing your first manuscript for publication” separately.

Primary analyses will be handled with the intention-to-treat approach. The analyses will include all individuals with valid data regardless of they did attend the complete course. Missing data will be handled with multiple imputation [ 28 ] .

Upon reasonable request, public assess will be granted to protocol, datasets analysed during the current study, and statistical code Table 3 .

Oversight, monitoring, and adverse events

This project is coordinated in collaboration between the WHO CC (DEN-62) at the Parker Institute, CAMES, and the PhD School at the Faculty of Health and Medical Sciences, University of Copenhagen. The project leader runs the day-to-day support of the trial. The steering committee of the trial includes principal investigators from WHO CC (DEN-62) and CAMES and the project leader and meets approximately three times a year.

Data monitoring is done on a daily basis by the project leader and controlled by an external independent researcher.

An adverse event is “a harmful and negative outcome that happens when a patient has been provided with medical care” [ 29 ]. Since this trial does not involve patients in medical care, we do not expect adverse events. If participants decline taking part in the course after receiving the information of the course setting, information on reason for declining is sought obtained. If the reason is the setting this can be considered an unintended effect. Information of unintended effects of the online setting (the intervention) will be recorded. Participants are encouraged to contact the project leader with any response to the course in general both during and after the course.

The trial description has been sent to the Scientific Ethical Committee of the Capital Region of Denmark (VEK) (21041907), which assessed it as not necessary to notify and that it could proceed without permission from VEK according to the Danish law and regulation of scientific research. The trial is registered with the Danish Data Protection Agency (Privacy) (P-2022–158). Important protocol modification will be communicated to relevant parties as well as VEK, the Joint Regional Information Security and Clinicaltrials.gov within an as short timeframe as possible.

Dissemination plans

The results (positive, negative, or inconclusive) will be disseminated in educational, scientific, and clinical fora, in international scientific peer-reviewed journals, and clinicaltrials.gov will be updated upon completion of the trial. After scientific publication, the results will be disseminated to the public by the press, social media including the website of the hospital and other organizations – as well as internationally via WHO CC (DEN-62) at the Parker Institute and WHO Europe.

All authors will fulfil the ICMJE recommendations for authorship, and RR will be first author of the articles as a part of her PhD dissertation. Contributors who do not fulfil these recommendations will be offered acknowledgement in the article.

This cluster randomized trial investigates if an onsite setting of a research course for PhD students within the health and medical sciences is different from an online setting. The outcomes measured are learning of research methodology (primary), preference, motivation, and self-efficacy (secondary) on short term and academic achievements (secondary) on long term.

The results of this study will be discussed as follows:

Discussion of primary outcome

Primary outcome will be compared and contrasted with similar studies including recent RCTs and mixed-method studies on online and onsite research methodology courses within health and medical education [ 10 , 11 , 30 ] and for inspiration outside the field [ 31 , 32 ]: Tokalic finds similar outcomes for online and onsite, Martinic finds that the web-based educational intervention improves knowledge, Cheung concludes that the evidence is insufficient to say that the two modes have different learning outcomes, Kofoed finds online setting to have negative impact on learning and Rahimi-Ardabili presents positive self-reported student knowledge. These conflicting results will be discussed in the context of the result on the learning outcome of this study. The literature may change if more relevant studies are published.

Discussion of secondary outcomes

Secondary significant outcomes are compared and contrasted with similar studies.

Limitations, generalizability, bias and strengths

It is a limitation to this study, that an onsite curriculum for a full day is delivered identically online, as this may favour the onsite course due to screen fatigue [ 33 ]. At the same time, it is also a strength that the time schedules are similar in both settings. The offer of coffee, tea, water, and a plain sandwich in the onsite course may better facilitate the possibility for socializing. Another limitation is that the study is performed in Denmark within a specific educational culture, with institutional policies and resources which might affect the outcome and limit generalization to other geographical settings. However, international students are welcome in the class.

In educational interventions it is generally difficult to blind participants and this inherent limitation also applies to this trial [ 11 ]. Thus, the participants are not blinded to their assigned intervention, and neither are the lecturers in the courses. However, the external statistical expert will be blinded when doing the analyses.

We chose to compare in-person onsite setting with a synchronous online setting. Therefore, the online setting cannot be expected to generalize to asynchronous online setting. Asynchronous delivery has in some cases showed positive results and it might be because students could go back and forth through the modules in the interface without time limit [ 11 ].

We will report on all the outcomes defined prior to conducting the study to avoid selective reporting bias.

It is a strength of the study that it seeks to report outcomes within the 1, 2 and 4 levels of the Kirkpatrick conceptual framework, and not solely on level 1. It is also a strength that the study is cluster randomized which will reduce “infections” between the two settings and has an adequate power calculated sample size and looks for a relevant educational difference of 20% between the online and onsite setting.

Perspectives with implications for practice

The results of this study may have implications for the students for which educational setting they choose. Learning and preference results has implications for lecturers, course managers and curriculum developers which setting they should plan for the health and medical education. It may also be of inspiration for teaching and training in other disciplines. From a societal perspective it also has implications because we will know the effect and preferences of online learning in case of a future lock down.

Future research could investigate academic achievements in online and onsite research training on the long run (Kirkpatrick 4); the effect of blended learning versus online or onsite (Kirkpatrick 2); lecturers’ preferences for online and onsite setting within health and medical education (Kirkpatrick 1) and resource use in synchronous and asynchronous online learning (Kirkpatrick 5).

Trial status

This trial collected pilot data from August to September 2021 and opened for inclusion in January 2022. Completion of recruitment is expected in April 2024 and long-term follow-up in April 2026. Protocol version number 1 03.06.2022 with amendments 30.11.2023.

Availability of data and materials

The project leader will have access to the final trial dataset which will be available upon reasonable request. Exception to this is the qualitative raw data that might contain information leading to personal identification.

Abbreviations

Artificial Intelligence

Copenhagen academy for medical education and simulation

Confidence interval

Coronavirus disease

European credit transfer and accumulation system

International committee of medical journal editors

Intrinsic motivation inventory

Multiple choice questionnaire

Doctor of medicine

Masters of sciences

Randomized controlled trial

Scientific ethical committee of the Capital Region of Denmark

WHO Collaborating centre for evidence-based clinical health promotion

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Acknowledgements

We thank the students who make their evaluations available for this trial and MSc (Public Health) Mie Sylow Liljendahl for statistical support.

Open access funding provided by Copenhagen University The Parker Institute, which hosts the WHO CC (DEN-62), receives a core grant from the Oak Foundation (OCAY-18–774-OFIL). The Oak Foundation had no role in the design of the study or in the collection, analysis, and interpretation of the data or in writing the manuscript.

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Contributions

RR, LK and HT have made substantial contributions to the conception and design of the work; RR to the acquisition of data, and RR, LK and HT to the interpretation of data; RR has drafted the work and RR, LK, and HT have substantively revised it AND approved the submitted version AND agreed to be personally accountable for their own contributions as well as ensuring that any questions which relates to the accuracy or integrity of the work are adequately investigated, resolved and documented.

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Correspondence to Rie Raffing .

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Ethics approval and consent to participate.

The Danish National Committee on Health Research Ethics has assessed the study Journal-nr.:21041907 (Date: 21–09-2021) without objections or comments. The study has been approved by The Danish Data Protection Agency Journal-nr.: P-2022–158 (Date: 04.05.2022).

All PhD students participate after informed consent. They can withdraw from the study at any time without explanations or consequences for their education. They will be offered information of the results at study completion. There are no risks for the course participants as the measurements in the course follow routine procedure and they are not affected by the follow up in Google Scholar. However, the 15 min of filling in the forms may be considered inconvenient.

The project will follow the GDPR and the Joint Regional Information Security Policy. Names and ID numbers are stored on a secure and logged server at the Capital Region Denmark to avoid risk of data leak. All outcomes are part of the routine evaluation at the courses, except the follow up for academic achievement by publications and related indexes. However, the publications are publicly available per se.

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Raffing, R., Konge, L. & Tønnesen, H. Learning effect of online versus onsite education in health and medical scholarship – protocol for a cluster randomized trial. BMC Med Educ 24 , 927 (2024). https://doi.org/10.1186/s12909-024-05915-z

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Concordant fatal congenital anomaly in twin pregnancy: a case report and review of the literature

• Amenu Diriba 1 ,
• Temesgen Tilahun   ORCID: orcid.org/0000-0003-4138-4066 1 ,
• Lammii Gonfaa 1 ,
• Jemal Gebi 1 ,
• Bikila Lemi 1 ,
• Jiregna Fyera 1 ,
• Suleiman Mazeng 1 ,
• Aschalew Legesse 1 &
• Dinaol Alemu 1  

Journal of Medical Case Reports volume  18 , Article number:  406 ( 2024 ) Cite this article

Metrics details

When a pregnant mother finds out she has a fetus with a congenital defect, the parents feel profound worry, anxiety, and melancholy. Anomalies can happen in singleton or twin pregnancies, though they are more common in twin pregnancies. In twins, several congenital defects are typically discordant.

Case summary

We present a rare case of concordant fatal anomaly in twin pregnancy in a 22-year-old African patient primigravida mother from Western Ethiopia who presented for routine antenatal care. An obstetric ultrasound scan showed anencephaly, meningomyelocele, and severe ventriculomegaly. After receiving the counseling, the patient was admitted to the ward, and the pregnancy was terminated with the medical option. Following a successful in-patient stay, she was given folic acid supplements and instructed to get preconception counseling before getting pregnant again.

The case demonstrates the importance of early obstetric ultrasound examination and detailed anatomic scanning, in twin pregnancies in particular. This case also calls for routine preconceptional care.

Peer Review reports

Introduction

A “congenital anomaly” is defined as any abnormal deviation from the expected structure, form, or function. “Malformations” are morphological abnormalities of organs or regions of the body resulting from an intrinsically abnormal developmental process, whereas “disruptions” are defects from interference with an initially normal developmental process [ 1 , 2 ].

Congenital anomalies present in twins also include any anomaly that may occur in singletons, including primary structural malformations, chromosomal defects, and genetic syndromes [ 1 , 2 ]. The anomalies may involve one or both twins [ 2 , 3 ]. The former is called discordant, while the latter is termed concordant [ 1 , 2 , 3 ]. Due to the anomaly’s multifactorial inheritance pattern, which is influenced by both genetic and environmental factors, twins are usually discordant for this anomaly, with only one co-twin affected [ 1 , 3 ].

However, some research has shown that identical twins have concordant anomalies such as neural tube defects [ 3 , 4 ]. Here we present a rare case of concordant congenital anomaly in twin pregnancy.

Case presentation

This 22-year-old African patient primigravida from western Ethiopia came to Wallaga University Referral Hospital for her second appointment as part of her routine prenatal care schedule. She said she had been amenorrheic for the past 4 months, but she could not recall the last time she had had a regular menstrual cycle. She received folic acid 5 mg (orally daily and iron sulphate 325 mg orally three times daily for 3 months, and two doses of tetanus–diphtheria vaccine during her prenatal care. However, she had no preconceptional care.

In the course of the index pregnancy, she had never experienced headaches, vaginal bleeding, blurred vision, or epigastric pain. In addition, she had no history of smoking tobacco, chewing khat, drinking alcohol, or using other forms of medication. She had never had bronchial asthma, hypertension, diabetes mellitus, or heart disease.

There was no history of twin pregnancies in her family. This patient was diagnosed with hyperemesis gravidarum and hospitalized to the gynecology ward a month prior to the current presentation. She was released from the hospital after 2 days, having improved. It proved that the pregnancy was twins at 11 weeks appropriate for gestational age (AGA). However, no fetal anomaly was detected.

On examination, she was healthy-looking. Her vital signs were blood pressure (BP) = 120/70 mmHg, pulse rate (PR) = 84 beats per minute, respiratory rate (RR) = 20 breaths per minute, and a temperature of 37.6 °C. She had slightly pale conjunctiva. An abdominal exam showed a 20-week-sized gravid uterus. The lymph glandular system, respiratory system, cardiovascular system, and genitalia were normal. On neurologic examination, reflexes were intact, and meningeal signs were negative.

Urinalysis; complete blood count; random blood sugar (RBS); serology for syphilis, hepatitis, and human immunodeficiency virus (HIV); obstetrics ultrasound; and blood group were done. Obstetrics ultrasound showed a twin intrauterine pregnancy with an anencephalic twin A and severe ventriculomegaly and lumbar myelo-meningocele in twin B (Table  1 ).

With the final diagnosis of a second-trimester twin pregnancy with a concordant fatal anomaly, the patient was admitted to the gynecology ward. In the ward, the patient was given mifepristone 200 mg orally. After 24 hours, 400 µg of misoprostol was inserted vaginally. A total of 8 hours later, she expelled twin A, weighing 120 g of anencephalic abortus with cervical, thoracic, and lumbar vertebral defect, and twin B, weighing 150 g of hydrocephalic abortus with a thoracic and lumbar vertebral defect, and protrusion of the intestine via the right side para umbilical area without the covering membrane (Fig.  1 A, B). The placenta was monochorionic.

A Twin abortuses with neural tube defects at Wallaga University Referral Hospital, Western Ethiopia, 2023. B Twin abortuses with neural tube defects and gastroschisis at Wallaga University Referral Hospital, Western Ethiopia, 2023

When compared with singleton pregnancies, the rates of congenital anomalies are higher with multiple pregnancies [ 5 , 6 ]. In fetuses in multiple gestations, these anatomic abnormalities are more commonly linked to monozygotic (MZ) twining than dizygotic (DZ) twining [ 2 , 7 ].

Anomalies may affect all organ systems, but the commonest involve cardiovascular and central nervous systems, followed by ophthalmic and gastrointestinal abnormalities [ 1 , 4 , 7 , 8 ]. The concordance rate of major congenital malformations is around 20% for monozygotic twins, with most dizygotic twin pairs being discordant [ 1 ]. Only in certain organ systems do monozygotic twins exhibit higher concordance rates than DZ twins [ 4 , 7 ]. Our case is MZ twins. In both twins, the neural nervous system was affected. The twin pairs had neural tube defects. One twin had gastroschisis.

Anomalies in singleton and twin pregnancies are associated with maternal exposure to various factors such as diazepam use, cigarette smoking, maternal obesity, and nutritional deficiencies [ 9 ]. Our case was complicated by hyperemesis gravidarum. Because of repeated vomiting, it could result in nutritional deficiency, which could in turn result in neural tube defects and other anomalies.

There is limited published evidence about screening for structural abnormalities in twin or higher order pregnancies [ 10 ]. Careful sonographic surveys of fetal anatomy are indicated in multifetal pregnancies because the risk for congenital anomalies is increased [ 11 ]. A complete fetal anatomic survey is therefore recommended for all twin gestations at 18–22 weeks’ gestational age [ 12 ]. The accuracy of ultrasonography for detecting congenital fetal anomalies in multiple gestations has not been adequately studied in large series [ 11 ].

Following diagnosis of an anomaly affecting only one fetus, practitioners may face the dilemma of expectant management versus selective termination. If the option of selective fetocide is considered, the main variable determining the technique to achieve this aim is chorionicity [ 13 , 14 , 15 ]. In a dichorionic pregnancy, passage of fetocidal agents from one twin into the circulation of the co-twin is unlikely due to the lack of placental anastomoses [ 13 , 14 ]. When monochorionic (MC) twins are complicated with discordant fetal anomalies, the management scheme will be much more complex [ 13 , 14 ]. In this case, selective termination needs to be performed by ensuring complete and permanent occlusion of both the arterial and venous flows in the umbilical cord of the affected twin. Bipolar cord coagulation under ultrasound guidance is associated with approximately 70–80% survival rates [ 14 , 15 ]. However, management of concordant fatal anomaly in twin pregnancy is not controversial [ 3 ]. In our case, both twins had fatal congenital anomalies, which required immediate termination of the pregnancy using misoprostol.

Availability of data and materials

The datasets used during the current study are available from the corresponding author on reasonable request.

Abbreviations

Hepatitis B surface antigen

Human immunodeficiency virus

Monozygotic

Rhesus factor

Venereal disease research laboratory

White blood count

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Department of Obstetrics and Gynecology, School of Medicine, Wollega University, Nekemte, Ethiopia

Amenu Diriba, Temesgen Tilahun, Lammii Gonfaa, Jemal Gebi, Bikila Lemi, Jiregna Fyera,  Suleiman Mazeng, Aschalew Legesse & Dinaol Alemu

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All authors made a significant contribution to the work reported, whether that was in the conception, study design, execution, acquisition of data, analysis, and interpretation, or in all these areas; they took part in drafting, revising, or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted, and agree to be accountable for all aspects of the work.

AD is an assistant professor in the Department of Obstetrics and Gynecology, Institute of Health Sciences, Wollega University; TT is an associate professor of Obstetrics & Gynecology, Institute of Health Sciences, Wollega University; LG is an assistant professor in the Department of Obstetrics and gynecology, Institute of Health Sciences, Wollega University; JG is an assistant professor in the Department of Obstetrics and Gynecology, Institute of Health Sciences, Wollega University; JF is an assistant professor in the Department of Obstetrics and Gynecology, Institute of Health Sciences, Wollega University; BL is an assistant professor in the Department of Obstetrics and Gynecology, Institute of Health Sciences, Wollega University; S is an obstetrics and gynecology resident at the Institute of Health Sciences, Wollega University; AL is an obstetrics and gynecology resident at the Institute of Health Sciences, Wollega University; and DA is an obstetrics and gynecology resident at the Institute of Health Sciences, Wollega University.

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Diriba, A., Tilahun, T., Gonfaa, L. et al. Concordant fatal congenital anomaly in twin pregnancy: a case report and review of the literature. J Med Case Reports 18 , 406 (2024). https://doi.org/10.1186/s13256-024-04732-8

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High-cycle fatigue performance of laser powder bed fusion ti-6al-4v alloy with inherent internal defects: a critical literature review.

1. Introduction

2. The Internal Defects Problem of L-PBF Ti-6Al-4V

2.1. the role of internal defects on the fatigue performance.

2.2. Crack Initiation and Micro-Short Crack (MSC) Propagation

2.3. crack propagation, 3. microstructure, 3.1. microstructure in different states, 3.1.1. as-built alloys, 3.1.2. after post heat treatments, 3.1.3. after hip, 3.2. microstructure’s role in high-cycle fatigue performance, 4. post processing treatments, 4.1. machining, 4.2. heat treatment, 5. machine learning models of predicting fatigue life, 6. conclusions and perspective for future research.

• Research on different types of internal defects was extremely uneven, partially due to the occurrence frequency, detriment level, and difficulty of analysis for each defect type. As a result, gas porosity has been extensively and quantitatively investigated, recently followed by LOF defects. However, studies on other internal defect types, such as keyholes, balling, and α-phase facets, were rare. There is an urgent need for detailed research on these types of defects.
• Quantitatively correlating LOFs with fatigue life performance is challenging due to their complex topology. Recent studies suggested that LOFs can be simplified based on their main profile and most critical embedded features, using an adapted SWT method to evaluate fatigue life. Comprehensive investigations are needed to further digitalize the geometric features of LOFs with a validated analytical approach. Additionally, the influence of un-melted powders embedded in LOFs needs to be investigated and clarified.
• The microstructure composition of L-PBF Ti-6Al-4V alloy, especially in the as-built state, is distinct from conventionally manufactured Ti-6Al-4V alloy. Additionally, L-PBF Ti-6Al-4V alloy have more microstructural imperfections, such as dislocations, which introduce uncertainties in quantifying the microstructure’s role in early-stage crack evolution. To address this, the microstructures of L-PBF Ti-6Al-4V alloy under various conditions need to be standardized. Subsequently, the quantification of the microstructure’s role in fatigue life performance should be progressively investigated, starting with simple cases and advancing to more complex scenarios. This could begin with the fine α + β structure after heat treatment, progress to the α′ in the β phase of the as-built condition, and eventually include the coupling effects with internal defects.
• The surrounding microstructures around internal defects significantly influence fatigue crack initiation and MSC propagation. However, relevant research on AM Ti-6Al-4V alloy was very limited. While similar investigations on other types of metal alloys can be referenced, their findings cannot be directly applied due to distinct microstructures and properties. The CPFE approach may be an ideal solution to clarify the role of microstructures in fatigue life performance and reveal the mechanisms and behaviors of MSC propagation.
• The distribution of residual stresses in L-PBF Ti-6Al-4V alloy, in both as-built and post-treated states (e.g., machining, heat treatments, and HIP), has been investigated and visualized in recent years. Understanding the mechanism by which fatigue life performance is altered is straightforward: residual stresses superpose the remote stresses. However, there is an urgent need to quantitatively correlate residual stresses in different states with fatigue crack evolution. Numerical analysis of residual stress formation during L-PBF processing and post-processing treatments, as well as its impact on fatigue crack evolution, can be both necessary and valuable.
• Post-processing techniques have a considerable impact on the fatigue life performance of L-PBF Ti-6Al-4V alloy. There have been in-depth investigations into various post-processing parameters (e.g., heat treatment at different temperatures, HIP) and studies combining different post-processing treatments (e.g., machining, heat treatment, and HIP), as suggested by previous review papers. Further research in this direction is needed to establish standardized post-processing treatments and combinations to achieve an optimal balance of mechanical properties for various application purposes.
• Data-driven ML models seriously rely on the quantity and quality of dataset, and their contribution to the physical mechanism might be limited. Physics-informed ML models are more promising as they improve the prediction accuracy while requiring less data. In addition, they provide a deeper understanding of the physical mechanism than the pure data-driven models. FEA is an efficient solution for enlarging the dataset, on the premise of being validated.

Author Contributions

Data availability statement, conflicts of interest.

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Li, Z.; Affolter, C. High-Cycle Fatigue Performance of Laser Powder Bed Fusion Ti-6Al-4V Alloy with Inherent Internal Defects: A Critical Literature Review. Metals 2024 , 14 , 972. https://doi.org/10.3390/met14090972

Li Z, Affolter C. High-Cycle Fatigue Performance of Laser Powder Bed Fusion Ti-6Al-4V Alloy with Inherent Internal Defects: A Critical Literature Review. Metals . 2024; 14(9):972. https://doi.org/10.3390/met14090972

Li, Zongchen, and Christian Affolter. 2024. "High-Cycle Fatigue Performance of Laser Powder Bed Fusion Ti-6Al-4V Alloy with Inherent Internal Defects: A Critical Literature Review" Metals 14, no. 9: 972. https://doi.org/10.3390/met14090972

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Hope Credit Union review September 2024: Checking, savings, CDs, and more

Ashley Barnett is a seasoned financial writer with over 15 years of experience. Ashley is dedicated to empowering others through her writing and is committed to providing accessible financial guidance. She has been published at sites such as Forbes, CNN, and USA Today.

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Hope Credit Union offers one savings account and one Christmas Club account. Unfortunately, the interest rates earned are low compared to the best high-yield savings accounts . So, if you want to maximize the interest you earn on your savings, you’ll want to keep it elsewhere.

Savings account features

Christmas Club account features

Hope Credit Union savings rates compared to current top rates*

While Hope is a great option, there are some institutions that offer higher interest rates. Compare the rates above to this list of competitors:

Money market accounts

Hope Credit Union's MMA earns an unimpressive rate on balances under $100,000. It earns a higher rate on accounts above $100,000, but still not as high as you could find with the top MMAs .

Hope Credit Union MMA features

Share certificates

Like most credit unions, Hope Credit Union calls its CDs "share certificates." It offers several terms, ranging from six months to five years; however, interest rates are lower than those of the best CDs . 

Also, as with most CDs, there are early withdrawal penalties if you withdraw your funds before the end of the CD term. 

Hope Credit Union share certificate features

Other services Hope Credit Union offers  

• Individual retirement accounts (IRAs): You can open either a traditional or Roth IRA with a $25 minimum deposit. 
• Small business banking: If you have a small business, Hope Credit Union offers business checking and lending accounts. 
• Personal loans: Hope Credit Union offers several personal loans, including short-term loans, credit builder loans, and loans secured by a share certificate. 
• Auto loans: You can finance your next car at Hope Credit Union at a competitive rate. 
• Mortgages: In addition to traditional mortgages, Hope Credit Union also has loans specifically for low or moderate-income families. 
• Home equity loans: Hope Credit Union will let you borrow against the equity of your home
• Credit cards: Three credit cards are available, including a rewards card and a secured card. 
• Insurance: Hope Credit Union offers three types of insurance: Life insurance, auto and home insurance, and accident, disability, and dismemberment (AD&D) insurance. 

Online banking

You can view and manage your accounts on Hope Credit Union's website or mobile app. You can view statements, make mobile deposits, transfer funds, pay bills, view transactions, and more.

You can also contact customer support, apply for loans, and renew share certificates online. It has its own digital wallet. Hope Credit Union has all the features you would expect from the best online banks and credit unions . 

The Hope Credit Union platform and customer support  

Hope Credit Union can be reached via phone, email, and in person. The automated phone system is available 24/7 and you can reach live representatives Monday through Friday from 8 a.m. to 5 p.m. Central time.  

It also has branches across Alabama, Arkansas, Louisiana, Mississippi, and Tennessee. 

Is Hope Credit Union secure?

Yes, Hope Credit Union is secure. Your funds are protected by National Credit Union Administration (NCUA) insurance up to $250,000 per account type, per depositor. Therefore, if the credit union fails, your funds will be returned to you up to the limit. 

It also uses two-factor authentication (2FA) to keep your account safe, making it more difficult for hackers to access your information. Emails sent to and from your account are secure when you are logged into your account, either online or in the mobile app. 

Lastly, it does not share your information with its affiliates, which limits the chances of a data breach. 

Hope Credit Union user reviews

Recent online reviews of Hope Credit Union are mostly negative. It has an F rating from the Better Business Bureau (BBB), and other reviews on various platforms are also mostly negative. Most reviews state the agents are not friendly or knowledgeable. 

We contacted the credit union to clarify some account details. We first sent an email that was not answered. When we called, the agents were friendly but didn't readily have the answers to our questions and informed us they would send a follow-up email. The email arrived quickly and answered our questions fully. 

Compare Hope Credit Union alternatives

Is Hope Credit Union right for you?

Hope Credit Union is best for those who live in one of the five states Hope Credit Union serves and are looking to improve their credit. They have several unique personal loans that are designed specifically for those who have less-than-perfect credit, such as credit building loans, borrow and save loans, and secured loans.  

However, if you want to maximize the interest you earn on your savings, Hope may not be the best choice for you. 

Frequently asked questions

How do i open an account with hope credit union.

If you aren't already a member, you will need to pay a $10 fee to join the credit union. After that, opening an account is similar to other banks. You can open an account online or in person and will need two forms of ID, one being a government-issued ID, proof of address, your membership fee, and an opening deposit.

Is Hope Credit Union NCUA-insured?

Hope Credit Union is NCUA-insured. This means that if the credit union were to go out of business, your deposits would be protected up to $250,000 per account type, per owner.

What credit score do you need with Hope Credit Union?

Hope Credit Union has lending options for those with lower credit scores. It can work with borrowers with credit scores as low as 580.

• Term deposit investors should check our ranking of the best CD rates .
• Pick one the best high-yield savings accounts to maximize your earnings.
• Earn a better return on your investment with one of the best savings accounts .
• Opting for one of the best free checking accounts means you won’t pay a dime for checking.
• The best checking account bonuses can help you grow your money even faster.
• Our ranking of the best online banks guides you to the best home for all your banking needs.

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EDITORIAL DISCLOSURE : The advice, opinions, or rankings contained in this article are solely those of the Fortune Recommends ™ editorial team. This content has not been reviewed or endorsed by any of our affiliate partners or other third parties.

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The 100 Best Books of the 21st Century: A Printable List

By The New York Times Books Staff Aug. 26, 2024

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The New York Times Book Review I've I want THE 100 BEST BOOKS OF THE 21ST CENTURY read to it read it 1 My Brilliant Friend, by Elena Ferrante 26 26 Atonement, by lan McEwan 2 The Warmth of Other Suns, by Isabel Wilkerson 27 Americanah, by Chimamanda Ngozi Adichie 3 Wolf Hall, by Hilary Mantel 28 Cloud Atlas, by David Mitchell 4 The Known World, by Edward P. Jones 29 The Last Samurai, by Helen DeWitt 5 The Corrections, by Jonathan Franzen 30 Sing, Unburied, Sing, by Jesmyn Ward 6 2666, by Roberto Bolaño 31 White Teeth, by Zadie Smith 7 The Underground Railroad, by Colson Whitehead 32 The Line of Beauty, by Alan Hollinghurst 8 Austerlitz, by W.G. Sebald 33 Salvage the Bones, by Jesmyn Ward 9 Never Let Me Go, by Kazuo Ishiguro 34 Citizen, by Claudia Rankine 10 Gilead, by Marilynne Robinson 35 Fun Home, by Alison Bechdel 11 The Brief Wondrous Life of Oscar Wao, by Junot Díaz 36 Between the World and Me, by Ta-Nehisi Coates 12 The Year of Magical Thinking, by Joan Didion 37 The Years, by Annie Ernaux 13 The Road, by Cormac McCarthy 38 The Savage Detectives, by Roberto Bolaño 14 Outline, by Rachel Cusk 39 A Visit From the Goon Squad, by Jennifer Egan 15 Pachinko, by Min Jin Lee 40 H Is for Hawk, by Helen Macdonald 16 The Amazing Adventures of Kavalier & Clay, by Michael Chabon 41 Small Things Like These, by Claire Keegan 17 The Sellout, by Paul Beatty 42 A Brief History of Seven Killings, by Marlon James 18 Lincoln in the Bardo, by George Saunders 43 Postwar, by Tony Judt 19 Say Nothing, by Patrick Radden Keefe 44 The Fifth Season, by N.K. Jemisin 20 Erasure, by Percival Everrett 45 The Argonauts, by Maggie Nelson 21 Evicted, by Matthew Desmond 46 The Goldfinch, by Donna Tartt 22 22 Behind the Beautiful Forevers, by Katherine Boo 47 A Mercy, by Toni Morrison 23 Hateship, Friendship, Courtship, Loveship, Marriage, by Alice Munro 48 Persepolis, by Marjane Satrapi 24 The Overstory, by Richard Powers 49 The Vegetarian, by Han Kang 25 25 Random Family, by Adrian Nicole LeBlanc 50 Trust, by Hernan Diaz I've I want read to it read it

The New York Times Book Review I've I want THE 100 BEST BOOKS OF THE 21ST CENTURY read to it read it 51 Life After Life, by Kate Atkinson 52 52 Train Dreams, by Denis Johnson 53 Runaway, by Alice Munro 76 77 An American Marriage, by Tayari Jones 78 Septology, by Jon Fosse Tomorrow, and Tomorrow, and Tomorrow, by Gabrielle Zevin 54 Tenth of December, by George Saunders 55 The Looming Tower, by Lawrence Wright 56 The Flamethrowers, by Rachel Kushner 57 Nickel and Dimed, by Barbara Ehrenreich ཤྲཱ རྒྱ སྐྱ A Manual for Cleaning Women, by Lucia Berlin The Story of the Lost Child, by Elena Ferrante Pulphead, by John Jeremiah Sullivan. Hurricane Season, by Fernanda Melchor 58 Stay True, by Hua Hsu 83 When We Cease to Understand the World, by Benjamín Labatut 59 Middlesex, by Jeffrey Eugenides 84 The Emperor of All Maladies, by Siddhartha Mukherjee 60 Heavy, by Kiese Laymon 85 Pastoralia, by George Saunders 61 Demon Copperhead, by Barbara Kingsolver 86 Frederick Douglass, by David W. Blight 62 10:04, by Ben Lerner 87 Detransition, Baby, by Torrey Peters 63 Veronica, by Mary Gaitskill 88 The Collected Stories of Lydia Davis 64 The Great Believers, by Rebecca Makkai 89 The Return, by Hisham Matar 65 The Plot Against America, by Philip Roth 90 The Sympathizer, by Viet Thanh Nguyen 66 We the Animals, by Justin Torres 91 The Human Stain, by Philip Roth 67 Far From the Tree, by Andrew Solomon 92 The Days of Abandonment, by Elena Ferrante 68 The Friend, by Sigrid Nunez 93 Station Eleven, by Emily St. John Mandel 69 59 The New Jim Crow, by Michelle Alexander 94 On Beauty, by Zadie Smith 10 70 All Aunt Hagar's Children, by Edward P. Jones 95 Bring Up the Bodies, by Hilary Mantel 71 The Copenhagen Trilogy, by Tove Ditlevsen 96 Wayward Lives, Beautiful Experiments, by Saidiya Hartman 72 22 Secondhand Time, by Svetlana Alexievich 97 Men We Reaped, by Jesmyn Ward 73 The Passage of Power, by Robert A. Caro 98 Bel Canto, by Ann Patchett 74 Olive Kitteridge, by Elizabeth Strout 99 How to Be Both, by Ali Smith 75 15 Exit West, by Mohsin Hamid 100 Tree of Smoke, by Denis Johnson I've I want read to it read it

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• Effects of muscle strength training combined with aerobic training versus aerobic training alone on cardiovascular disease risk indicators in patients with coronary artery disease: a systematic review and meta-analysis of randomised clinical trials
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• http://orcid.org/0000-0002-6623-6994 Tasuku Terada 1 , 2 ,
• Robert Pap 3 ,
• Abby Thomas 4 ,
• Roger Wei 5 ,
• Takumi Noda 6 , 7 ,
• Sarah Visintini 8 ,
• Jennifer L Reed 2 , 9 , 10
• 1 Physiology, Pharmacology and Neuroscience, School of Life Sciences , University of Nottingham , Nottingham , UK
• 2 Exercise Physiology and Cardiovascular Health Lab, Division of Cardiac Prevention and Rehabilitation, University of Ottawa Heart Institute , Ottawa , ON , Canada
• 3 University of Alberta Faculty of Medicine & Dentistry , Edmonton , AB , Canada
• 4 Department of Community Health Sciences , University of Calgary , Calgary , AB , Canada
• 5 Faculty of Medicine , University of Ottawa , Ottawa , ON , Canada
• 6 Graduate School of Medical Sciences, Department of Rehabilitation Sciences , Kitasato University , Sagamihara , Japan
• 7 Department of Cardiovascular Rehabilitation, National Cerebral and Cardiovascular Center , Suita , Japan
• 8 Berkman Library , University of Ottawa Heart Institute , Ottawa , ON , Canada
• 9 School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa , Ottawa , ON , Canada
• 10 School of Human Kinetics, Faculty of Health Sciences, University of Ottawa , Ottawa , ON , Canada
• Correspondence to Dr Tasuku Terada; tasuku.terada{at}nottingham.ac.uk

Objective To compare the effects of aerobic training combined with muscle strength training (hereafter referred to as combined training) to aerobic training alone on cardiovascular disease risk indicators in patients with coronary artery disease (CAD).

Design Systematic review with meta-analysis.

Data sources MEDLINE, Embase, CINAHL, SPORTDiscus, Scopus, trial registries and grey literature sources were searched in February 2024.

Eligibility criteria Randomised clinical trials comparing the effects of ≥4 weeks of combined training and aerobic training alone on at least one of the following outcomes: cardiorespiratory fitness (CRF), anthropometric and haemodynamic measures and cardiometabolic blood biomarkers in patients with CAD.

Results Of 13 246 studies screened, 23 were included (N=916). Combined training was more effective in increasing CRF (standard mean difference (SMD) 0.26, 95% CI 0.02 to 0.49, p=0.03) and lean body mass (mean difference (MD) 0.78 kg, 95% CI 0.39 kg to 1.17 kg, p<0.001), and reducing per cent body fat (MD −2.2%, 95% CI −3.5% to −0.9%, p=0.001) compared with aerobic training alone. There were no differences in the cardiometabolic biomarkers between the groups. Our subgroup analyses showed that combined training increases CRF more than aerobic training alone when muscle strength training was added to aerobic training without compromising aerobic training volume (SMD 0.36, 95% CI 0.05 to 0.68, p=0.02).

Conclusion Combined training had greater effects on CRF and body composition than aerobic training alone in patients with CAD. To promote an increase in CRF in patients with CAD, muscle strength training should be added to aerobic training without reducing aerobic exercise volume.

Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information.

https://doi.org/10.1136/bjsports-2024-108530

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Contributors TT is the guarantor. TT drafted the manuscript. TT and SV contributed to the development of the selection and data extraction criteria. SV developed the search strategy. TT, AT, RW, RP and TN screened studies for inclusion. TT, AT, RW, RP and TN extracted information on adherence and adverse events. TT and PR completed the risk of bias assessments. RP and JR critically reviewed the manuscript. All authors read and approved the final manuscript.

Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Competing interests None declared.

Provenance and peer review Not commissioned; externally peer reviewed.

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Watch CBS News

Harris and Trump have competing tax plans. Here's how your paycheck would change under both.

By Aimee Picchi

Edited By Alain Sherter

Updated on: August 30, 2024 / 4:48 PM EDT / CBS News

Presidential candidates commonly trot out new tax proposals as part of their campaign platforms, often pledging to help ease the financial burden on taxpayers. This year, the plans emerging from rivals Kamala Harris and Donald Trump could affect voters' paychecks in very different ways. 

Former President Donald Trump would seek to extend the tax cuts enacted through the Tax Cuts and Jobs Act, his signature 2017 legislation that reduced taxes for most Americans, although research has shown the top earners received the biggest benefits. He's also proposing to eliminate taxes on tips  and on  Social Security income , while also lowering the corporate tax rate.

Vice President Harris has proposed introducing more generous tax benefits for families , as well as hiking the corporate tax rate to help offset spending from bigger tax credits. 

The two proposals reflect different views of how best to support U.S. families and fuel economic growth. On the one hand, Trump's plan would provide tax cuts for all income groups, but the biggest winners would be higher-income Americans. The greatest benefits under Harris' plan would go to the lowest-income Americans, while she would up the taxes of the top-earning households. 

"It's true that Trump looks like he's winner for everybody, but he'll provide much bigger giveaways to the top 1% and top 0.1%, whereas Harris will be negative for these people," said Kent Smetters, faculty director of the Penn Wharton Budget Model, a group within the University of Pennsylvania's Wharton School that analyzes the budgetary impact of government policies. 

Ultimately, both plans would come with significant price tags, although the combination of Trump's tax cuts for corporations and individuals would prove more expensive, Penn Wharton forecast. It estimates that his proposal would add $5.8 trillion to the federal deficit over the next decade, compared with $2 trillion for Harris' plan. 

In an email, Republican National Committee spokesperson Anna Kelly said that Trump's tax policies will "shrink deficits" as well as "lower long-term debt levels" through cuts in federal spending, increasing energy production and deregulation.

The Harris-Walz campaign, meanwhile, is pointing to the Penn Wharton Budget Model's analysis as evidence that Trump would create a "deficit bomb agenda." 

"Donald Trump's campaign may want to mute Donald Trump on the debate stage, but they can't mute our strong economy and Trump's disastrous agenda that will explode the deficit, increase costs on the middle class by nearly $4,000 a year, and send our economy hurtling into a recession by mid-next year," Harris-Walz spokesman James Singer said in an email.

"Explosive" deficit?

Although Harris' tax proposal would potentially have a smaller impact on the nation's deficit than Trump, Smetters noted that both parties would ultimately add to the nation's growing fiscal burden. 

The federal budget deficit in fiscal year 2024 is projected to hit $1.9 trillion, the Congressional Budget Office forecast in June. That represents a 27% increase from its prior February forecast, due partly to new funding provided to Ukraine, Israel and other countries. 

Deficits may seem abstract to many taxpayers, but at the simplest level they show the country is spending more than it's taking in through tax revenue. That, in turn, increases the national debt to finance the deficit. Many economists warn that comes with a cost, such as higher interest payments to service that growing debt. 

"Essentially we're on this explosive path right now," Smetters said. 

At some point, soaring U.S. debt could sow doubt in capital markets about the federal government's ability to either raise taxes or cut spending enough to avoid defaulting on that debt, he added.

"Neither candidate is being serious about addressing the big issue —the house is burning down and the candidates are arguing over the furniture," Smetters said. "They are just making things worse and harming the economy."

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Aimee Picchi is the associate managing editor for CBS MoneyWatch, where she covers business and personal finance. She previously worked at Bloomberg News and has written for national news outlets including USA Today and Consumer Reports.

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• How to Write a Literature Review | Guide, Examples, & Templates

How to Write a Literature Review | Guide, Examples, & Templates

Published on January 2, 2023 by Shona McCombes . Revised on September 11, 2023.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research that you can later apply to your paper, thesis, or dissertation topic .

There are five key steps to writing a literature review:

• Search for relevant literature
• Evaluate sources
• Identify themes, debates, and gaps
• Outline the structure
• Write your literature review

A good literature review doesn’t just summarize sources—it analyzes, synthesizes , and critically evaluates to give a clear picture of the state of knowledge on the subject.

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Table of contents

What is the purpose of a literature review, examples of literature reviews, step 1 – search for relevant literature, step 2 – evaluate and select sources, step 3 – identify themes, debates, and gaps, step 4 – outline your literature review’s structure, step 5 – write your literature review, free lecture slides, other interesting articles, frequently asked questions, introduction.

• Quick Run-through
• Step 1 & 2

When you write a thesis , dissertation , or research paper , you will likely have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

• Demonstrate your familiarity with the topic and its scholarly context
• Develop a theoretical framework and methodology for your research
• Position your work in relation to other researchers and theorists
• Show how your research addresses a gap or contributes to a debate
• Evaluate the current state of research and demonstrate your knowledge of the scholarly debates around your topic.

Writing literature reviews is a particularly important skill if you want to apply for graduate school or pursue a career in research. We’ve written a step-by-step guide that you can follow below.

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Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

• Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
• Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
• Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
• Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research problem and questions .

Make a list of keywords

Start by creating a list of keywords related to your research question. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list as you discover new keywords in the process of your literature search.

• Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
• Body image, self-perception, self-esteem, mental health
• Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some useful databases to search for journals and articles include:

• Your university’s library catalogue
• Google Scholar
• Project Muse (humanities and social sciences)
• Medline (life sciences and biomedicine)
• EconLit (economics)
• Inspec (physics, engineering and computer science)

You can also use boolean operators to help narrow down your search.

Make sure to read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

You likely won’t be able to read absolutely everything that has been written on your topic, so it will be necessary to evaluate which sources are most relevant to your research question.

For each publication, ask yourself:

• What question or problem is the author addressing?
• What are the key concepts and how are they defined?
• What are the key theories, models, and methods?
• Does the research use established frameworks or take an innovative approach?
• What are the results and conclusions of the study?
• How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
• What are the strengths and weaknesses of the research?

Make sure the sources you use are credible , and make sure you read any landmark studies and major theories in your field of research.

You can use our template to summarize and evaluate sources you’re thinking about using. Click on either button below to download.

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It is important to keep track of your sources with citations to avoid plagiarism . It can be helpful to make an annotated bibliography , where you compile full citation information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

Receive feedback on language, structure, and formatting

Professional editors proofread and edit your paper by focusing on:

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See an example

To begin organizing your literature review’s argument and structure, be sure you understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

• Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
• Themes: what questions or concepts recur across the literature?
• Debates, conflicts and contradictions: where do sources disagree?
• Pivotal publications: are there any influential theories or studies that changed the direction of the field?
• Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

• Most research has focused on young women.
• There is an increasing interest in the visual aspects of social media.
• But there is still a lack of robust research on highly visual platforms like Instagram and Snapchat—this is a gap that you could address in your own research.

There are various approaches to organizing the body of a literature review. Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarizing sources in order.

Try to analyze patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organize your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

• Look at what results have emerged in qualitative versus quantitative research
• Discuss how the topic has been approached by empirical versus theoretical scholarship
• Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text , your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, you can follow these tips:

• Summarize and synthesize: give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: don’t just paraphrase other researchers — add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically evaluate: mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: use transition words and topic sentences to draw connections, comparisons and contrasts

In the conclusion, you should summarize the key findings you have taken from the literature and emphasize their significance.

When you’ve finished writing and revising your literature review, don’t forget to proofread thoroughly before submitting. Not a language expert? Check out Scribbr’s professional proofreading services !

This article has been adapted into lecture slides that you can use to teach your students about writing a literature review.

Scribbr slides are free to use, customize, and distribute for educational purposes.

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If you want to know more about the research process , methodology , research bias , or statistics , make sure to check out some of our other articles with explanations and examples.

• Sampling methods
• Simple random sampling
• Stratified sampling
• Cluster sampling
• Likert scales
• Reproducibility

 Statistics

• Null hypothesis
• Statistical power
• Probability distribution
• Effect size
• Poisson distribution

Research bias

• Optimism bias
• Cognitive bias
• Implicit bias
• Hawthorne effect
• Anchoring bias
• Explicit bias

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a thesis, dissertation , or research paper , in order to situate your work in relation to existing knowledge.

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarize yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

The literature review usually comes near the beginning of your thesis or dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

A literature review is a survey of credible sources on a topic, often used in dissertations , theses, and research papers . Literature reviews give an overview of knowledge on a subject, helping you identify relevant theories and methods, as well as gaps in existing research. Literature reviews are set up similarly to other  academic texts , with an introduction , a main body, and a conclusion .

An  annotated bibliography is a list of  source references that has a short description (called an annotation ) for each of the sources. It is often assigned as part of the research process for a  paper .  

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• 04 December 2020
• Correction 09 December 2020

How to write a superb literature review

Andy Tay is a freelance writer based in Singapore.

You can also search for this author in PubMed   Google Scholar

Literature reviews are important resources for scientists. They provide historical context for a field while offering opinions on its future trajectory. Creating them can provide inspiration for one’s own research, as well as some practice in writing. But few scientists are trained in how to write a review — or in what constitutes an excellent one. Even picking the appropriate software to use can be an involved decision (see ‘Tools and techniques’). So Nature asked editors and working scientists with well-cited reviews for their tips.

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doi: https://doi.org/10.1038/d41586-020-03422-x

Interviews have been edited for length and clarity.

Updates & Corrections

Correction 09 December 2020 : An earlier version of the tables in this article included some incorrect details about the programs Zotero, Endnote and Manubot. These have now been corrected.

Hsing, I.-M., Xu, Y. & Zhao, W. Electroanalysis 19 , 755–768 (2007).

Article   Google Scholar  

Ledesma, H. A. et al. Nature Nanotechnol. 14 , 645–657 (2019).

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Brahlek, M., Koirala, N., Bansal, N. & Oh, S. Solid State Commun. 215–216 , 54–62 (2015).

Choi, Y. & Lee, S. Y. Nature Rev. Chem . https://doi.org/10.1038/s41570-020-00221-w (2020).

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Writing a Literature Review

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A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays). When we say “literature review” or refer to “the literature,” we are talking about the research ( scholarship ) in a given field. You will often see the terms “the research,” “the scholarship,” and “the literature” used mostly interchangeably.

Where, when, and why would I write a lit review?

There are a number of different situations where you might write a literature review, each with slightly different expectations; different disciplines, too, have field-specific expectations for what a literature review is and does. For instance, in the humanities, authors might include more overt argumentation and interpretation of source material in their literature reviews, whereas in the sciences, authors are more likely to report study designs and results in their literature reviews; these differences reflect these disciplines’ purposes and conventions in scholarship. You should always look at examples from your own discipline and talk to professors or mentors in your field to be sure you understand your discipline’s conventions, for literature reviews as well as for any other genre.

A literature review can be a part of a research paper or scholarly article, usually falling after the introduction and before the research methods sections. In these cases, the lit review just needs to cover scholarship that is important to the issue you are writing about; sometimes it will also cover key sources that informed your research methodology.

Lit reviews can also be standalone pieces, either as assignments in a class or as publications. In a class, a lit review may be assigned to help students familiarize themselves with a topic and with scholarship in their field, get an idea of the other researchers working on the topic they’re interested in, find gaps in existing research in order to propose new projects, and/or develop a theoretical framework and methodology for later research. As a publication, a lit review usually is meant to help make other scholars’ lives easier by collecting and summarizing, synthesizing, and analyzing existing research on a topic. This can be especially helpful for students or scholars getting into a new research area, or for directing an entire community of scholars toward questions that have not yet been answered.

What are the parts of a lit review?

Most lit reviews use a basic introduction-body-conclusion structure; if your lit review is part of a larger paper, the introduction and conclusion pieces may be just a few sentences while you focus most of your attention on the body. If your lit review is a standalone piece, the introduction and conclusion take up more space and give you a place to discuss your goals, research methods, and conclusions separately from where you discuss the literature itself.

Introduction:

• An introductory paragraph that explains what your working topic and thesis is
• A forecast of key topics or texts that will appear in the review
• Potentially, a description of how you found sources and how you analyzed them for inclusion and discussion in the review (more often found in published, standalone literature reviews than in lit review sections in an article or research paper)
• Summarize and synthesize: Give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: Don’t just paraphrase other researchers – add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically Evaluate: Mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: Use transition words and topic sentence to draw connections, comparisons, and contrasts.

Conclusion:

• Summarize the key findings you have taken from the literature and emphasize their significance
• Connect it back to your primary research question

How should I organize my lit review?

Lit reviews can take many different organizational patterns depending on what you are trying to accomplish with the review. Here are some examples:

• Chronological : The simplest approach is to trace the development of the topic over time, which helps familiarize the audience with the topic (for instance if you are introducing something that is not commonly known in your field). If you choose this strategy, be careful to avoid simply listing and summarizing sources in order. Try to analyze the patterns, turning points, and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred (as mentioned previously, this may not be appropriate in your discipline — check with a teacher or mentor if you’re unsure).
• Thematic : If you have found some recurring central themes that you will continue working with throughout your piece, you can organize your literature review into subsections that address different aspects of the topic. For example, if you are reviewing literature about women and religion, key themes can include the role of women in churches and the religious attitude towards women.
• Qualitative versus quantitative research
• Empirical versus theoretical scholarship
• Divide the research by sociological, historical, or cultural sources
• Theoretical : In many humanities articles, the literature review is the foundation for the theoretical framework. You can use it to discuss various theories, models, and definitions of key concepts. You can argue for the relevance of a specific theoretical approach or combine various theorical concepts to create a framework for your research.

What are some strategies or tips I can use while writing my lit review?

Any lit review is only as good as the research it discusses; make sure your sources are well-chosen and your research is thorough. Don’t be afraid to do more research if you discover a new thread as you’re writing. More info on the research process is available in our "Conducting Research" resources .

As you’re doing your research, create an annotated bibliography ( see our page on the this type of document ). Much of the information used in an annotated bibliography can be used also in a literature review, so you’ll be not only partially drafting your lit review as you research, but also developing your sense of the larger conversation going on among scholars, professionals, and any other stakeholders in your topic.

Usually you will need to synthesize research rather than just summarizing it. This means drawing connections between sources to create a picture of the scholarly conversation on a topic over time. Many student writers struggle to synthesize because they feel they don’t have anything to add to the scholars they are citing; here are some strategies to help you:

• It often helps to remember that the point of these kinds of syntheses is to show your readers how you understand your research, to help them read the rest of your paper.
• Writing teachers often say synthesis is like hosting a dinner party: imagine all your sources are together in a room, discussing your topic. What are they saying to each other?
• Look at the in-text citations in each paragraph. Are you citing just one source for each paragraph? This usually indicates summary only. When you have multiple sources cited in a paragraph, you are more likely to be synthesizing them (not always, but often
• Read more about synthesis here.

The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn’t work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it. You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources.

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Handbook of eHealth Evaluation: An Evidence-based Approach [Internet].

Chapter 9 methods for literature reviews.

Guy Paré and Spyros Kitsiou .

9.1. Introduction

Literature reviews play a critical role in scholarship because science remains, first and foremost, a cumulative endeavour ( vom Brocke et al., 2009 ). As in any academic discipline, rigorous knowledge syntheses are becoming indispensable in keeping up with an exponentially growing eHealth literature, assisting practitioners, academics, and graduate students in finding, evaluating, and synthesizing the contents of many empirical and conceptual papers. Among other methods, literature reviews are essential for: (a) identifying what has been written on a subject or topic; (b) determining the extent to which a specific research area reveals any interpretable trends or patterns; (c) aggregating empirical findings related to a narrow research question to support evidence-based practice; (d) generating new frameworks and theories; and (e) identifying topics or questions requiring more investigation ( Paré, Trudel, Jaana, & Kitsiou, 2015 ).

Literature reviews can take two major forms. The most prevalent one is the “literature review” or “background” section within a journal paper or a chapter in a graduate thesis. This section synthesizes the extant literature and usually identifies the gaps in knowledge that the empirical study addresses ( Sylvester, Tate, & Johnstone, 2013 ). It may also provide a theoretical foundation for the proposed study, substantiate the presence of the research problem, justify the research as one that contributes something new to the cumulated knowledge, or validate the methods and approaches for the proposed study ( Hart, 1998 ; Levy & Ellis, 2006 ).

The second form of literature review, which is the focus of this chapter, constitutes an original and valuable work of research in and of itself ( Paré et al., 2015 ). Rather than providing a base for a researcher’s own work, it creates a solid starting point for all members of the community interested in a particular area or topic ( Mulrow, 1987 ). The so-called “review article” is a journal-length paper which has an overarching purpose to synthesize the literature in a field, without collecting or analyzing any primary data ( Green, Johnson, & Adams, 2006 ).

When appropriately conducted, review articles represent powerful information sources for practitioners looking for state-of-the art evidence to guide their decision-making and work practices ( Paré et al., 2015 ). Further, high-quality reviews become frequently cited pieces of work which researchers seek out as a first clear outline of the literature when undertaking empirical studies ( Cooper, 1988 ; Rowe, 2014 ). Scholars who track and gauge the impact of articles have found that review papers are cited and downloaded more often than any other type of published article ( Cronin, Ryan, & Coughlan, 2008 ; Montori, Wilczynski, Morgan, Haynes, & Hedges, 2003 ; Patsopoulos, Analatos, & Ioannidis, 2005 ). The reason for their popularity may be the fact that reading the review enables one to have an overview, if not a detailed knowledge of the area in question, as well as references to the most useful primary sources ( Cronin et al., 2008 ). Although they are not easy to conduct, the commitment to complete a review article provides a tremendous service to one’s academic community ( Paré et al., 2015 ; Petticrew & Roberts, 2006 ). Most, if not all, peer-reviewed journals in the fields of medical informatics publish review articles of some type.

The main objectives of this chapter are fourfold: (a) to provide an overview of the major steps and activities involved in conducting a stand-alone literature review; (b) to describe and contrast the different types of review articles that can contribute to the eHealth knowledge base; (c) to illustrate each review type with one or two examples from the eHealth literature; and (d) to provide a series of recommendations for prospective authors of review articles in this domain.

9.2. Overview of the Literature Review Process and Steps

As explained in Templier and Paré (2015) , there are six generic steps involved in conducting a review article:

• formulating the research question(s) and objective(s),
• searching the extant literature,
• screening for inclusion,
• assessing the quality of primary studies,
• extracting data, and
• analyzing data.

Although these steps are presented here in sequential order, one must keep in mind that the review process can be iterative and that many activities can be initiated during the planning stage and later refined during subsequent phases ( Finfgeld-Connett & Johnson, 2013 ; Kitchenham & Charters, 2007 ).

Formulating the research question(s) and objective(s): As a first step, members of the review team must appropriately justify the need for the review itself ( Petticrew & Roberts, 2006 ), identify the review’s main objective(s) ( Okoli & Schabram, 2010 ), and define the concepts or variables at the heart of their synthesis ( Cooper & Hedges, 2009 ; Webster & Watson, 2002 ). Importantly, they also need to articulate the research question(s) they propose to investigate ( Kitchenham & Charters, 2007 ). In this regard, we concur with Jesson, Matheson, and Lacey (2011) that clearly articulated research questions are key ingredients that guide the entire review methodology; they underscore the type of information that is needed, inform the search for and selection of relevant literature, and guide or orient the subsequent analysis. Searching the extant literature: The next step consists of searching the literature and making decisions about the suitability of material to be considered in the review ( Cooper, 1988 ). There exist three main coverage strategies. First, exhaustive coverage means an effort is made to be as comprehensive as possible in order to ensure that all relevant studies, published and unpublished, are included in the review and, thus, conclusions are based on this all-inclusive knowledge base. The second type of coverage consists of presenting materials that are representative of most other works in a given field or area. Often authors who adopt this strategy will search for relevant articles in a small number of top-tier journals in a field ( Paré et al., 2015 ). In the third strategy, the review team concentrates on prior works that have been central or pivotal to a particular topic. This may include empirical studies or conceptual papers that initiated a line of investigation, changed how problems or questions were framed, introduced new methods or concepts, or engendered important debate ( Cooper, 1988 ). Screening for inclusion: The following step consists of evaluating the applicability of the material identified in the preceding step ( Levy & Ellis, 2006 ; vom Brocke et al., 2009 ). Once a group of potential studies has been identified, members of the review team must screen them to determine their relevance ( Petticrew & Roberts, 2006 ). A set of predetermined rules provides a basis for including or excluding certain studies. This exercise requires a significant investment on the part of researchers, who must ensure enhanced objectivity and avoid biases or mistakes. As discussed later in this chapter, for certain types of reviews there must be at least two independent reviewers involved in the screening process and a procedure to resolve disagreements must also be in place ( Liberati et al., 2009 ; Shea et al., 2009 ). Assessing the quality of primary studies: In addition to screening material for inclusion, members of the review team may need to assess the scientific quality of the selected studies, that is, appraise the rigour of the research design and methods. Such formal assessment, which is usually conducted independently by at least two coders, helps members of the review team refine which studies to include in the final sample, determine whether or not the differences in quality may affect their conclusions, or guide how they analyze the data and interpret the findings ( Petticrew & Roberts, 2006 ). Ascribing quality scores to each primary study or considering through domain-based evaluations which study components have or have not been designed and executed appropriately makes it possible to reflect on the extent to which the selected study addresses possible biases and maximizes validity ( Shea et al., 2009 ). Extracting data: The following step involves gathering or extracting applicable information from each primary study included in the sample and deciding what is relevant to the problem of interest ( Cooper & Hedges, 2009 ). Indeed, the type of data that should be recorded mainly depends on the initial research questions ( Okoli & Schabram, 2010 ). However, important information may also be gathered about how, when, where and by whom the primary study was conducted, the research design and methods, or qualitative/quantitative results ( Cooper & Hedges, 2009 ). Analyzing and synthesizing data : As a final step, members of the review team must collate, summarize, aggregate, organize, and compare the evidence extracted from the included studies. The extracted data must be presented in a meaningful way that suggests a new contribution to the extant literature ( Jesson et al., 2011 ). Webster and Watson (2002) warn researchers that literature reviews should be much more than lists of papers and should provide a coherent lens to make sense of extant knowledge on a given topic. There exist several methods and techniques for synthesizing quantitative (e.g., frequency analysis, meta-analysis) and qualitative (e.g., grounded theory, narrative analysis, meta-ethnography) evidence ( Dixon-Woods, Agarwal, Jones, Young, & Sutton, 2005 ; Thomas & Harden, 2008 ).

9.3. Types of Review Articles and Brief Illustrations

EHealth researchers have at their disposal a number of approaches and methods for making sense out of existing literature, all with the purpose of casting current research findings into historical contexts or explaining contradictions that might exist among a set of primary research studies conducted on a particular topic. Our classification scheme is largely inspired from Paré and colleagues’ (2015) typology. Below we present and illustrate those review types that we feel are central to the growth and development of the eHealth domain.

9.3.1. Narrative Reviews

The narrative review is the “traditional” way of reviewing the extant literature and is skewed towards a qualitative interpretation of prior knowledge ( Sylvester et al., 2013 ). Put simply, a narrative review attempts to summarize or synthesize what has been written on a particular topic but does not seek generalization or cumulative knowledge from what is reviewed ( Davies, 2000 ; Green et al., 2006 ). Instead, the review team often undertakes the task of accumulating and synthesizing the literature to demonstrate the value of a particular point of view ( Baumeister & Leary, 1997 ). As such, reviewers may selectively ignore or limit the attention paid to certain studies in order to make a point. In this rather unsystematic approach, the selection of information from primary articles is subjective, lacks explicit criteria for inclusion and can lead to biased interpretations or inferences ( Green et al., 2006 ). There are several narrative reviews in the particular eHealth domain, as in all fields, which follow such an unstructured approach ( Silva et al., 2015 ; Paul et al., 2015 ).

Despite these criticisms, this type of review can be very useful in gathering together a volume of literature in a specific subject area and synthesizing it. As mentioned above, its primary purpose is to provide the reader with a comprehensive background for understanding current knowledge and highlighting the significance of new research ( Cronin et al., 2008 ). Faculty like to use narrative reviews in the classroom because they are often more up to date than textbooks, provide a single source for students to reference, and expose students to peer-reviewed literature ( Green et al., 2006 ). For researchers, narrative reviews can inspire research ideas by identifying gaps or inconsistencies in a body of knowledge, thus helping researchers to determine research questions or formulate hypotheses. Importantly, narrative reviews can also be used as educational articles to bring practitioners up to date with certain topics of issues ( Green et al., 2006 ).

Recently, there have been several efforts to introduce more rigour in narrative reviews that will elucidate common pitfalls and bring changes into their publication standards. Information systems researchers, among others, have contributed to advancing knowledge on how to structure a “traditional” review. For instance, Levy and Ellis (2006) proposed a generic framework for conducting such reviews. Their model follows the systematic data processing approach comprised of three steps, namely: (a) literature search and screening; (b) data extraction and analysis; and (c) writing the literature review. They provide detailed and very helpful instructions on how to conduct each step of the review process. As another methodological contribution, vom Brocke et al. (2009) offered a series of guidelines for conducting literature reviews, with a particular focus on how to search and extract the relevant body of knowledge. Last, Bandara, Miskon, and Fielt (2011) proposed a structured, predefined and tool-supported method to identify primary studies within a feasible scope, extract relevant content from identified articles, synthesize and analyze the findings, and effectively write and present the results of the literature review. We highly recommend that prospective authors of narrative reviews consult these useful sources before embarking on their work.

Darlow and Wen (2015) provide a good example of a highly structured narrative review in the eHealth field. These authors synthesized published articles that describe the development process of mobile health (m-health) interventions for patients’ cancer care self-management. As in most narrative reviews, the scope of the research questions being investigated is broad: (a) how development of these systems are carried out; (b) which methods are used to investigate these systems; and (c) what conclusions can be drawn as a result of the development of these systems. To provide clear answers to these questions, a literature search was conducted on six electronic databases and Google Scholar . The search was performed using several terms and free text words, combining them in an appropriate manner. Four inclusion and three exclusion criteria were utilized during the screening process. Both authors independently reviewed each of the identified articles to determine eligibility and extract study information. A flow diagram shows the number of studies identified, screened, and included or excluded at each stage of study selection. In terms of contributions, this review provides a series of practical recommendations for m-health intervention development.

9.3.2. Descriptive or Mapping Reviews

The primary goal of a descriptive review is to determine the extent to which a body of knowledge in a particular research topic reveals any interpretable pattern or trend with respect to pre-existing propositions, theories, methodologies or findings ( King & He, 2005 ; Paré et al., 2015 ). In contrast with narrative reviews, descriptive reviews follow a systematic and transparent procedure, including searching, screening and classifying studies ( Petersen, Vakkalanka, & Kuzniarz, 2015 ). Indeed, structured search methods are used to form a representative sample of a larger group of published works ( Paré et al., 2015 ). Further, authors of descriptive reviews extract from each study certain characteristics of interest, such as publication year, research methods, data collection techniques, and direction or strength of research outcomes (e.g., positive, negative, or non-significant) in the form of frequency analysis to produce quantitative results ( Sylvester et al., 2013 ). In essence, each study included in a descriptive review is treated as the unit of analysis and the published literature as a whole provides a database from which the authors attempt to identify any interpretable trends or draw overall conclusions about the merits of existing conceptualizations, propositions, methods or findings ( Paré et al., 2015 ). In doing so, a descriptive review may claim that its findings represent the state of the art in a particular domain ( King & He, 2005 ).

In the fields of health sciences and medical informatics, reviews that focus on examining the range, nature and evolution of a topic area are described by Anderson, Allen, Peckham, and Goodwin (2008) as mapping reviews . Like descriptive reviews, the research questions are generic and usually relate to publication patterns and trends. There is no preconceived plan to systematically review all of the literature although this can be done. Instead, researchers often present studies that are representative of most works published in a particular area and they consider a specific time frame to be mapped.

An example of this approach in the eHealth domain is offered by DeShazo, Lavallie, and Wolf (2009). The purpose of this descriptive or mapping review was to characterize publication trends in the medical informatics literature over a 20-year period (1987 to 2006). To achieve this ambitious objective, the authors performed a bibliometric analysis of medical informatics citations indexed in medline using publication trends, journal frequencies, impact factors, Medical Subject Headings (MeSH) term frequencies, and characteristics of citations. Findings revealed that there were over 77,000 medical informatics articles published during the covered period in numerous journals and that the average annual growth rate was 12%. The MeSH term analysis also suggested a strong interdisciplinary trend. Finally, average impact scores increased over time with two notable growth periods. Overall, patterns in research outputs that seem to characterize the historic trends and current components of the field of medical informatics suggest it may be a maturing discipline (DeShazo et al., 2009).

9.3.3. Scoping Reviews

Scoping reviews attempt to provide an initial indication of the potential size and nature of the extant literature on an emergent topic (Arksey & O’Malley, 2005; Daudt, van Mossel, & Scott, 2013 ; Levac, Colquhoun, & O’Brien, 2010). A scoping review may be conducted to examine the extent, range and nature of research activities in a particular area, determine the value of undertaking a full systematic review (discussed next), or identify research gaps in the extant literature ( Paré et al., 2015 ). In line with their main objective, scoping reviews usually conclude with the presentation of a detailed research agenda for future works along with potential implications for both practice and research.

Unlike narrative and descriptive reviews, the whole point of scoping the field is to be as comprehensive as possible, including grey literature (Arksey & O’Malley, 2005). Inclusion and exclusion criteria must be established to help researchers eliminate studies that are not aligned with the research questions. It is also recommended that at least two independent coders review abstracts yielded from the search strategy and then the full articles for study selection ( Daudt et al., 2013 ). The synthesized evidence from content or thematic analysis is relatively easy to present in tabular form (Arksey & O’Malley, 2005; Thomas & Harden, 2008 ).

One of the most highly cited scoping reviews in the eHealth domain was published by Archer, Fevrier-Thomas, Lokker, McKibbon, and Straus (2011) . These authors reviewed the existing literature on personal health record ( phr ) systems including design, functionality, implementation, applications, outcomes, and benefits. Seven databases were searched from 1985 to March 2010. Several search terms relating to phr s were used during this process. Two authors independently screened titles and abstracts to determine inclusion status. A second screen of full-text articles, again by two independent members of the research team, ensured that the studies described phr s. All in all, 130 articles met the criteria and their data were extracted manually into a database. The authors concluded that although there is a large amount of survey, observational, cohort/panel, and anecdotal evidence of phr benefits and satisfaction for patients, more research is needed to evaluate the results of phr implementations. Their in-depth analysis of the literature signalled that there is little solid evidence from randomized controlled trials or other studies through the use of phr s. Hence, they suggested that more research is needed that addresses the current lack of understanding of optimal functionality and usability of these systems, and how they can play a beneficial role in supporting patient self-management ( Archer et al., 2011 ).

9.3.4. Forms of Aggregative Reviews

Healthcare providers, practitioners, and policy-makers are nowadays overwhelmed with large volumes of information, including research-based evidence from numerous clinical trials and evaluation studies, assessing the effectiveness of health information technologies and interventions ( Ammenwerth & de Keizer, 2004 ; Deshazo et al., 2009 ). It is unrealistic to expect that all these disparate actors will have the time, skills, and necessary resources to identify the available evidence in the area of their expertise and consider it when making decisions. Systematic reviews that involve the rigorous application of scientific strategies aimed at limiting subjectivity and bias (i.e., systematic and random errors) can respond to this challenge.

Systematic reviews attempt to aggregate, appraise, and synthesize in a single source all empirical evidence that meet a set of previously specified eligibility criteria in order to answer a clearly formulated and often narrow research question on a particular topic of interest to support evidence-based practice ( Liberati et al., 2009 ). They adhere closely to explicit scientific principles ( Liberati et al., 2009 ) and rigorous methodological guidelines (Higgins & Green, 2008) aimed at reducing random and systematic errors that can lead to deviations from the truth in results or inferences. The use of explicit methods allows systematic reviews to aggregate a large body of research evidence, assess whether effects or relationships are in the same direction and of the same general magnitude, explain possible inconsistencies between study results, and determine the strength of the overall evidence for every outcome of interest based on the quality of included studies and the general consistency among them ( Cook, Mulrow, & Haynes, 1997 ). The main procedures of a systematic review involve:

• Formulating a review question and developing a search strategy based on explicit inclusion criteria for the identification of eligible studies (usually described in the context of a detailed review protocol).
• Searching for eligible studies using multiple databases and information sources, including grey literature sources, without any language restrictions.
• Selecting studies, extracting data, and assessing risk of bias in a duplicate manner using two independent reviewers to avoid random or systematic errors in the process.
• Analyzing data using quantitative or qualitative methods.
• Presenting results in summary of findings tables.
• Interpreting results and drawing conclusions.

Many systematic reviews, but not all, use statistical methods to combine the results of independent studies into a single quantitative estimate or summary effect size. Known as meta-analyses , these reviews use specific data extraction and statistical techniques (e.g., network, frequentist, or Bayesian meta-analyses) to calculate from each study by outcome of interest an effect size along with a confidence interval that reflects the degree of uncertainty behind the point estimate of effect ( Borenstein, Hedges, Higgins, & Rothstein, 2009 ; Deeks, Higgins, & Altman, 2008 ). Subsequently, they use fixed or random-effects analysis models to combine the results of the included studies, assess statistical heterogeneity, and calculate a weighted average of the effect estimates from the different studies, taking into account their sample sizes. The summary effect size is a value that reflects the average magnitude of the intervention effect for a particular outcome of interest or, more generally, the strength of a relationship between two variables across all studies included in the systematic review. By statistically combining data from multiple studies, meta-analyses can create more precise and reliable estimates of intervention effects than those derived from individual studies alone, when these are examined independently as discrete sources of information.

The review by Gurol-Urganci, de Jongh, Vodopivec-Jamsek, Atun, and Car (2013) on the effects of mobile phone messaging reminders for attendance at healthcare appointments is an illustrative example of a high-quality systematic review with meta-analysis. Missed appointments are a major cause of inefficiency in healthcare delivery with substantial monetary costs to health systems. These authors sought to assess whether mobile phone-based appointment reminders delivered through Short Message Service ( sms ) or Multimedia Messaging Service ( mms ) are effective in improving rates of patient attendance and reducing overall costs. To this end, they conducted a comprehensive search on multiple databases using highly sensitive search strategies without language or publication-type restrictions to identify all rct s that are eligible for inclusion. In order to minimize the risk of omitting eligible studies not captured by the original search, they supplemented all electronic searches with manual screening of trial registers and references contained in the included studies. Study selection, data extraction, and risk of bias assessments were performed inde­­pen­dently by two coders using standardized methods to ensure consistency and to eliminate potential errors. Findings from eight rct s involving 6,615 participants were pooled into meta-analyses to calculate the magnitude of effects that mobile text message reminders have on the rate of attendance at healthcare appointments compared to no reminders and phone call reminders.

Meta-analyses are regarded as powerful tools for deriving meaningful conclusions. However, there are situations in which it is neither reasonable nor appropriate to pool studies together using meta-analytic methods simply because there is extensive clinical heterogeneity between the included studies or variation in measurement tools, comparisons, or outcomes of interest. In these cases, systematic reviews can use qualitative synthesis methods such as vote counting, content analysis, classification schemes and tabulations, as an alternative approach to narratively synthesize the results of the independent studies included in the review. This form of review is known as qualitative systematic review.

A rigorous example of one such review in the eHealth domain is presented by Mickan, Atherton, Roberts, Heneghan, and Tilson (2014) on the use of handheld computers by healthcare professionals and their impact on access to information and clinical decision-making. In line with the methodological guide­lines for systematic reviews, these authors: (a) developed and registered with prospero ( www.crd.york.ac.uk/ prospero / ) an a priori review protocol; (b) conducted comprehensive searches for eligible studies using multiple databases and other supplementary strategies (e.g., forward searches); and (c) subsequently carried out study selection, data extraction, and risk of bias assessments in a duplicate manner to eliminate potential errors in the review process. Heterogeneity between the included studies in terms of reported outcomes and measures precluded the use of meta-analytic methods. To this end, the authors resorted to using narrative analysis and synthesis to describe the effectiveness of handheld computers on accessing information for clinical knowledge, adherence to safety and clinical quality guidelines, and diagnostic decision-making.

In recent years, the number of systematic reviews in the field of health informatics has increased considerably. Systematic reviews with discordant findings can cause great confusion and make it difficult for decision-makers to interpret the review-level evidence ( Moher, 2013 ). Therefore, there is a growing need for appraisal and synthesis of prior systematic reviews to ensure that decision-making is constantly informed by the best available accumulated evidence. Umbrella reviews , also known as overviews of systematic reviews, are tertiary types of evidence synthesis that aim to accomplish this; that is, they aim to compare and contrast findings from multiple systematic reviews and meta-analyses ( Becker & Oxman, 2008 ). Umbrella reviews generally adhere to the same principles and rigorous methodological guidelines used in systematic reviews. However, the unit of analysis in umbrella reviews is the systematic review rather than the primary study ( Becker & Oxman, 2008 ). Unlike systematic reviews that have a narrow focus of inquiry, umbrella reviews focus on broader research topics for which there are several potential interventions ( Smith, Devane, Begley, & Clarke, 2011 ). A recent umbrella review on the effects of home telemonitoring interventions for patients with heart failure critically appraised, compared, and synthesized evidence from 15 systematic reviews to investigate which types of home telemonitoring technologies and forms of interventions are more effective in reducing mortality and hospital admissions ( Kitsiou, Paré, & Jaana, 2015 ).

9.3.5. Realist Reviews

Realist reviews are theory-driven interpretative reviews developed to inform, enhance, or supplement conventional systematic reviews by making sense of heterogeneous evidence about complex interventions applied in diverse contexts in a way that informs policy decision-making ( Greenhalgh, Wong, Westhorp, & Pawson, 2011 ). They originated from criticisms of positivist systematic reviews which centre on their “simplistic” underlying assumptions ( Oates, 2011 ). As explained above, systematic reviews seek to identify causation. Such logic is appropriate for fields like medicine and education where findings of randomized controlled trials can be aggregated to see whether a new treatment or intervention does improve outcomes. However, many argue that it is not possible to establish such direct causal links between interventions and outcomes in fields such as social policy, management, and information systems where for any intervention there is unlikely to be a regular or consistent outcome ( Oates, 2011 ; Pawson, 2006 ; Rousseau, Manning, & Denyer, 2008 ).

To circumvent these limitations, Pawson, Greenhalgh, Harvey, and Walshe (2005) have proposed a new approach for synthesizing knowledge that seeks to unpack the mechanism of how “complex interventions” work in particular contexts. The basic research question — what works? — which is usually associated with systematic reviews changes to: what is it about this intervention that works, for whom, in what circumstances, in what respects and why? Realist reviews have no particular preference for either quantitative or qualitative evidence. As a theory-building approach, a realist review usually starts by articulating likely underlying mechanisms and then scrutinizes available evidence to find out whether and where these mechanisms are applicable ( Shepperd et al., 2009 ). Primary studies found in the extant literature are viewed as case studies which can test and modify the initial theories ( Rousseau et al., 2008 ).

The main objective pursued in the realist review conducted by Otte-Trojel, de Bont, Rundall, and van de Klundert (2014) was to examine how patient portals contribute to health service delivery and patient outcomes. The specific goals were to investigate how outcomes are produced and, most importantly, how variations in outcomes can be explained. The research team started with an exploratory review of background documents and research studies to identify ways in which patient portals may contribute to health service delivery and patient outcomes. The authors identified six main ways which represent “educated guesses” to be tested against the data in the evaluation studies. These studies were identified through a formal and systematic search in four databases between 2003 and 2013. Two members of the research team selected the articles using a pre-established list of inclusion and exclusion criteria and following a two-step procedure. The authors then extracted data from the selected articles and created several tables, one for each outcome category. They organized information to bring forward those mechanisms where patient portals contribute to outcomes and the variation in outcomes across different contexts.

9.3.6. Critical Reviews

Lastly, critical reviews aim to provide a critical evaluation and interpretive analysis of existing literature on a particular topic of interest to reveal strengths, weaknesses, contradictions, controversies, inconsistencies, and/or other important issues with respect to theories, hypotheses, research methods or results ( Baumeister & Leary, 1997 ; Kirkevold, 1997 ). Unlike other review types, critical reviews attempt to take a reflective account of the research that has been done in a particular area of interest, and assess its credibility by using appraisal instruments or critical interpretive methods. In this way, critical reviews attempt to constructively inform other scholars about the weaknesses of prior research and strengthen knowledge development by giving focus and direction to studies for further improvement ( Kirkevold, 1997 ).

Kitsiou, Paré, and Jaana (2013) provide an example of a critical review that assessed the methodological quality of prior systematic reviews of home telemonitoring studies for chronic patients. The authors conducted a comprehensive search on multiple databases to identify eligible reviews and subsequently used a validated instrument to conduct an in-depth quality appraisal. Results indicate that the majority of systematic reviews in this particular area suffer from important methodological flaws and biases that impair their internal validity and limit their usefulness for clinical and decision-making purposes. To this end, they provide a number of recommendations to strengthen knowledge development towards improving the design and execution of future reviews on home telemonitoring.

9.4. Summary

Table 9.1 outlines the main types of literature reviews that were described in the previous sub-sections and summarizes the main characteristics that distinguish one review type from another. It also includes key references to methodological guidelines and useful sources that can be used by eHealth scholars and researchers for planning and developing reviews.

Typology of Literature Reviews (adapted from Paré et al., 2015).

As shown in Table 9.1 , each review type addresses different kinds of research questions or objectives, which subsequently define and dictate the methods and approaches that need to be used to achieve the overarching goal(s) of the review. For example, in the case of narrative reviews, there is greater flexibility in searching and synthesizing articles ( Green et al., 2006 ). Researchers are often relatively free to use a diversity of approaches to search, identify, and select relevant scientific articles, describe their operational characteristics, present how the individual studies fit together, and formulate conclusions. On the other hand, systematic reviews are characterized by their high level of systematicity, rigour, and use of explicit methods, based on an “a priori” review plan that aims to minimize bias in the analysis and synthesis process (Higgins & Green, 2008). Some reviews are exploratory in nature (e.g., scoping/mapping reviews), whereas others may be conducted to discover patterns (e.g., descriptive reviews) or involve a synthesis approach that may include the critical analysis of prior research ( Paré et al., 2015 ). Hence, in order to select the most appropriate type of review, it is critical to know before embarking on a review project, why the research synthesis is conducted and what type of methods are best aligned with the pursued goals.

9.5. Concluding Remarks

In light of the increased use of evidence-based practice and research generating stronger evidence ( Grady et al., 2011 ; Lyden et al., 2013 ), review articles have become essential tools for summarizing, synthesizing, integrating or critically appraising prior knowledge in the eHealth field. As mentioned earlier, when rigorously conducted review articles represent powerful information sources for eHealth scholars and practitioners looking for state-of-the-art evidence. The typology of literature reviews we used herein will allow eHealth researchers, graduate students and practitioners to gain a better understanding of the similarities and differences between review types.

We must stress that this classification scheme does not privilege any specific type of review as being of higher quality than another ( Paré et al., 2015 ). As explained above, each type of review has its own strengths and limitations. Having said that, we realize that the methodological rigour of any review — be it qualitative, quantitative or mixed — is a critical aspect that should be considered seriously by prospective authors. In the present context, the notion of rigour refers to the reliability and validity of the review process described in section 9.2. For one thing, reliability is related to the reproducibility of the review process and steps, which is facilitated by a comprehensive documentation of the literature search process, extraction, coding and analysis performed in the review. Whether the search is comprehensive or not, whether it involves a methodical approach for data extraction and synthesis or not, it is important that the review documents in an explicit and transparent manner the steps and approach that were used in the process of its development. Next, validity characterizes the degree to which the review process was conducted appropriately. It goes beyond documentation and reflects decisions related to the selection of the sources, the search terms used, the period of time covered, the articles selected in the search, and the application of backward and forward searches ( vom Brocke et al., 2009 ). In short, the rigour of any review article is reflected by the explicitness of its methods (i.e., transparency) and the soundness of the approach used. We refer those interested in the concepts of rigour and quality to the work of Templier and Paré (2015) which offers a detailed set of methodological guidelines for conducting and evaluating various types of review articles.

To conclude, our main objective in this chapter was to demystify the various types of literature reviews that are central to the continuous development of the eHealth field. It is our hope that our descriptive account will serve as a valuable source for those conducting, evaluating or using reviews in this important and growing domain.

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• Cite this Page Paré G, Kitsiou S. Chapter 9 Methods for Literature Reviews. In: Lau F, Kuziemsky C, editors. Handbook of eHealth Evaluation: An Evidence-based Approach [Internet]. Victoria (BC): University of Victoria; 2017 Feb 27.
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• Overview of the Literature Review Process and Steps
• Types of Review Articles and Brief Illustrations
• Concluding Remarks

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What is a Literature Review? How to Write It (with Examples)

A literature review is a critical analysis and synthesis of existing research on a particular topic. It provides an overview of the current state of knowledge, identifies gaps, and highlights key findings in the literature. 1 The purpose of a literature review is to situate your own research within the context of existing scholarship, demonstrating your understanding of the topic and showing how your work contributes to the ongoing conversation in the field. Learning how to write a literature review is a critical tool for successful research. Your ability to summarize and synthesize prior research pertaining to a certain topic demonstrates your grasp on the topic of study, and assists in the learning process. 

Table of Contents

• What is the purpose of literature review? 
• a. Habitat Loss and Species Extinction: 
• b. Range Shifts and Phenological Changes: 
• c. Ocean Acidification and Coral Reefs: 
• d. Adaptive Strategies and Conservation Efforts: 

How to write a good literature review 

• Choose a Topic and Define the Research Question: 
• Decide on the Scope of Your Review: 
• Select Databases for Searches: 
• Conduct Searches and Keep Track: 
• Review the Literature: 
• Organize and Write Your Literature Review: 
• How to write a literature review faster with Paperpal? 
• Frequently asked questions 

What is a literature review?

A well-conducted literature review demonstrates the researcher’s familiarity with the existing literature, establishes the context for their own research, and contributes to scholarly conversations on the topic. One of the purposes of a literature review is also to help researchers avoid duplicating previous work and ensure that their research is informed by and builds upon the existing body of knowledge.

What is the purpose of literature review?

A literature review serves several important purposes within academic and research contexts. Here are some key objectives and functions of a literature review: 2  

1. Contextualizing the Research Problem: The literature review provides a background and context for the research problem under investigation. It helps to situate the study within the existing body of knowledge. 

2. Identifying Gaps in Knowledge: By identifying gaps, contradictions, or areas requiring further research, the researcher can shape the research question and justify the significance of the study. This is crucial for ensuring that the new research contributes something novel to the field. 

Find academic papers related to your research topic faster. Try Research on Paperpal  

3. Understanding Theoretical and Conceptual Frameworks: Literature reviews help researchers gain an understanding of the theoretical and conceptual frameworks used in previous studies. This aids in the development of a theoretical framework for the current research. 

4. Providing Methodological Insights: Another purpose of literature reviews is that it allows researchers to learn about the methodologies employed in previous studies. This can help in choosing appropriate research methods for the current study and avoiding pitfalls that others may have encountered. 

5. Establishing Credibility: A well-conducted literature review demonstrates the researcher’s familiarity with existing scholarship, establishing their credibility and expertise in the field. It also helps in building a solid foundation for the new research. 

6. Informing Hypotheses or Research Questions: The literature review guides the formulation of hypotheses or research questions by highlighting relevant findings and areas of uncertainty in existing literature. 

Literature review example

Let’s delve deeper with a literature review example: Let’s say your literature review is about the impact of climate change on biodiversity. You might format your literature review into sections such as the effects of climate change on habitat loss and species extinction, phenological changes, and marine biodiversity. Each section would then summarize and analyze relevant studies in those areas, highlighting key findings and identifying gaps in the research. The review would conclude by emphasizing the need for further research on specific aspects of the relationship between climate change and biodiversity. The following literature review template provides a glimpse into the recommended literature review structure and content, demonstrating how research findings are organized around specific themes within a broader topic. 

Literature Review on Climate Change Impacts on Biodiversity:

Climate change is a global phenomenon with far-reaching consequences, including significant impacts on biodiversity. This literature review synthesizes key findings from various studies: 

a. Habitat Loss and Species Extinction:

Climate change-induced alterations in temperature and precipitation patterns contribute to habitat loss, affecting numerous species (Thomas et al., 2004). The review discusses how these changes increase the risk of extinction, particularly for species with specific habitat requirements. 

b. Range Shifts and Phenological Changes:

Observations of range shifts and changes in the timing of biological events (phenology) are documented in response to changing climatic conditions (Parmesan & Yohe, 2003). These shifts affect ecosystems and may lead to mismatches between species and their resources. 

c. Ocean Acidification and Coral Reefs:

The review explores the impact of climate change on marine biodiversity, emphasizing ocean acidification’s threat to coral reefs (Hoegh-Guldberg et al., 2007). Changes in pH levels negatively affect coral calcification, disrupting the delicate balance of marine ecosystems. 

d. Adaptive Strategies and Conservation Efforts:

Recognizing the urgency of the situation, the literature review discusses various adaptive strategies adopted by species and conservation efforts aimed at mitigating the impacts of climate change on biodiversity (Hannah et al., 2007). It emphasizes the importance of interdisciplinary approaches for effective conservation planning. 

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Writing a literature review involves summarizing and synthesizing existing research on a particular topic. A good literature review format should include the following elements. 

Introduction: The introduction sets the stage for your literature review, providing context and introducing the main focus of your review. 

• Opening Statement: Begin with a general statement about the broader topic and its significance in the field. 
• Scope and Purpose: Clearly define the scope of your literature review. Explain the specific research question or objective you aim to address. 
• Organizational Framework: Briefly outline the structure of your literature review, indicating how you will categorize and discuss the existing research. 
• Significance of the Study: Highlight why your literature review is important and how it contributes to the understanding of the chosen topic. 
• Thesis Statement: Conclude the introduction with a concise thesis statement that outlines the main argument or perspective you will develop in the body of the literature review. 

Body: The body of the literature review is where you provide a comprehensive analysis of existing literature, grouping studies based on themes, methodologies, or other relevant criteria. 

• Organize by Theme or Concept: Group studies that share common themes, concepts, or methodologies. Discuss each theme or concept in detail, summarizing key findings and identifying gaps or areas of disagreement. 
• Critical Analysis: Evaluate the strengths and weaknesses of each study. Discuss the methodologies used, the quality of evidence, and the overall contribution of each work to the understanding of the topic. 
• Synthesis of Findings: Synthesize the information from different studies to highlight trends, patterns, or areas of consensus in the literature. 
• Identification of Gaps: Discuss any gaps or limitations in the existing research and explain how your review contributes to filling these gaps. 
• Transition between Sections: Provide smooth transitions between different themes or concepts to maintain the flow of your literature review. 

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Conclusion: The conclusion of your literature review should summarize the main findings, highlight the contributions of the review, and suggest avenues for future research. 

• Summary of Key Findings: Recap the main findings from the literature and restate how they contribute to your research question or objective. 
• Contributions to the Field: Discuss the overall contribution of your literature review to the existing knowledge in the field. 
• Implications and Applications: Explore the practical implications of the findings and suggest how they might impact future research or practice. 
• Recommendations for Future Research: Identify areas that require further investigation and propose potential directions for future research in the field. 
• Final Thoughts: Conclude with a final reflection on the importance of your literature review and its relevance to the broader academic community. 

Conducting a literature review

Conducting a literature review is an essential step in research that involves reviewing and analyzing existing literature on a specific topic. It’s important to know how to do a literature review effectively, so here are the steps to follow: 1  

Choose a Topic and Define the Research Question:

• Select a topic that is relevant to your field of study. 
• Clearly define your research question or objective. Determine what specific aspect of the topic do you want to explore? 

Decide on the Scope of Your Review:

• Determine the timeframe for your literature review. Are you focusing on recent developments, or do you want a historical overview? 
• Consider the geographical scope. Is your review global, or are you focusing on a specific region? 
• Define the inclusion and exclusion criteria. What types of sources will you include? Are there specific types of studies or publications you will exclude? 

Select Databases for Searches:

• Identify relevant databases for your field. Examples include PubMed, IEEE Xplore, Scopus, Web of Science, and Google Scholar. 
• Consider searching in library catalogs, institutional repositories, and specialized databases related to your topic. 

Conduct Searches and Keep Track:

• Develop a systematic search strategy using keywords, Boolean operators (AND, OR, NOT), and other search techniques. 
• Record and document your search strategy for transparency and replicability. 
• Keep track of the articles, including publication details, abstracts, and links. Use citation management tools like EndNote, Zotero, or Mendeley to organize your references. 

Review the Literature:

• Evaluate the relevance and quality of each source. Consider the methodology, sample size, and results of studies. 
• Organize the literature by themes or key concepts. Identify patterns, trends, and gaps in the existing research. 
• Summarize key findings and arguments from each source. Compare and contrast different perspectives. 
• Identify areas where there is a consensus in the literature and where there are conflicting opinions. 
• Provide critical analysis and synthesis of the literature. What are the strengths and weaknesses of existing research? 

Organize and Write Your Literature Review:

• Literature review outline should be based on themes, chronological order, or methodological approaches. 
• Write a clear and coherent narrative that synthesizes the information gathered. 
• Use proper citations for each source and ensure consistency in your citation style (APA, MLA, Chicago, etc.). 
• Conclude your literature review by summarizing key findings, identifying gaps, and suggesting areas for future research. 

Whether you’re exploring a new research field or finding new angles to develop an existing topic, sifting through hundreds of papers can take more time than you have to spare. But what if you could find science-backed insights with verified citations in seconds? That’s the power of Paperpal’s new Research feature!  

How to write a literature review faster with Paperpal?

Paperpal, an AI writing assistant, integrates powerful academic search capabilities within its writing platform. With the Research feature, you get 100% factual insights, with citations backed by 250M+ verified research articles, directly within your writing interface with the option to save relevant references in your Citation Library. By eliminating the need to switch tabs to find answers to all your research questions, Paperpal saves time and helps you stay focused on your writing.   

Here’s how to use the Research feature:  

• Ask a question: Get started with a new document on paperpal.com. Click on the “Research” feature and type your question in plain English. Paperpal will scour over 250 million research articles, including conference papers and preprints, to provide you with accurate insights and citations. 
• Review and Save: Paperpal summarizes the information, while citing sources and listing relevant reads. You can quickly scan the results to identify relevant references and save these directly to your built-in citations library for later access. 
• Cite with Confidence: Paperpal makes it easy to incorporate relevant citations and references into your writing, ensuring your arguments are well-supported by credible sources. This translates to a polished, well-researched literature review. 

The literature review sample and detailed advice on writing and conducting a review will help you produce a well-structured report. But remember that a good literature review is an ongoing process, and it may be necessary to revisit and update it as your research progresses. By combining effortless research with an easy citation process, Paperpal Research streamlines the literature review process and empowers you to write faster and with more confidence. Try Paperpal Research now and see for yourself.  

Frequently asked questions

A literature review is a critical and comprehensive analysis of existing literature (published and unpublished works) on a specific topic or research question and provides a synthesis of the current state of knowledge in a particular field. A well-conducted literature review is crucial for researchers to build upon existing knowledge, avoid duplication of efforts, and contribute to the advancement of their field. It also helps researchers situate their work within a broader context and facilitates the development of a sound theoretical and conceptual framework for their studies.

Literature review is a crucial component of research writing, providing a solid background for a research paper’s investigation. The aim is to keep professionals up to date by providing an understanding of ongoing developments within a specific field, including research methods, and experimental techniques used in that field, and present that knowledge in the form of a written report. Also, the depth and breadth of the literature review emphasizes the credibility of the scholar in his or her field.  

Before writing a literature review, it’s essential to undertake several preparatory steps to ensure that your review is well-researched, organized, and focused. This includes choosing a topic of general interest to you and doing exploratory research on that topic, writing an annotated bibliography, and noting major points, especially those that relate to the position you have taken on the topic. 

Literature reviews and academic research papers are essential components of scholarly work but serve different purposes within the academic realm. 3 A literature review aims to provide a foundation for understanding the current state of research on a particular topic, identify gaps or controversies, and lay the groundwork for future research. Therefore, it draws heavily from existing academic sources, including books, journal articles, and other scholarly publications. In contrast, an academic research paper aims to present new knowledge, contribute to the academic discourse, and advance the understanding of a specific research question. Therefore, it involves a mix of existing literature (in the introduction and literature review sections) and original data or findings obtained through research methods. 

Literature reviews are essential components of academic and research papers, and various strategies can be employed to conduct them effectively. If you want to know how to write a literature review for a research paper, here are four common approaches that are often used by researchers.  Chronological Review: This strategy involves organizing the literature based on the chronological order of publication. It helps to trace the development of a topic over time, showing how ideas, theories, and research have evolved.  Thematic Review: Thematic reviews focus on identifying and analyzing themes or topics that cut across different studies. Instead of organizing the literature chronologically, it is grouped by key themes or concepts, allowing for a comprehensive exploration of various aspects of the topic.  Methodological Review: This strategy involves organizing the literature based on the research methods employed in different studies. It helps to highlight the strengths and weaknesses of various methodologies and allows the reader to evaluate the reliability and validity of the research findings.  Theoretical Review: A theoretical review examines the literature based on the theoretical frameworks used in different studies. This approach helps to identify the key theories that have been applied to the topic and assess their contributions to the understanding of the subject.  It’s important to note that these strategies are not mutually exclusive, and a literature review may combine elements of more than one approach. The choice of strategy depends on the research question, the nature of the literature available, and the goals of the review. Additionally, other strategies, such as integrative reviews or systematic reviews, may be employed depending on the specific requirements of the research.

The literature review format can vary depending on the specific publication guidelines. However, there are some common elements and structures that are often followed. Here is a general guideline for the format of a literature review:  Introduction:   Provide an overview of the topic.  Define the scope and purpose of the literature review.  State the research question or objective.  Body:   Organize the literature by themes, concepts, or chronology.  Critically analyze and evaluate each source.  Discuss the strengths and weaknesses of the studies.  Highlight any methodological limitations or biases.  Identify patterns, connections, or contradictions in the existing research.  Conclusion:   Summarize the key points discussed in the literature review.  Highlight the research gap.  Address the research question or objective stated in the introduction.  Highlight the contributions of the review and suggest directions for future research.

Both annotated bibliographies and literature reviews involve the examination of scholarly sources. While annotated bibliographies focus on individual sources with brief annotations, literature reviews provide a more in-depth, integrated, and comprehensive analysis of existing literature on a specific topic. The key differences are as follows: 

References 

• Denney, A. S., & Tewksbury, R. (2013). How to write a literature review.  Journal of criminal justice education ,  24 (2), 218-234. 
• Pan, M. L. (2016).  Preparing literature reviews: Qualitative and quantitative approaches . Taylor & Francis. 
• Cantero, C. (2019). How to write a literature review.  San José State University Writing Center . 

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Literature Review Guide

The literature review, database search tips.

• Back to Research Help
• What is a Literature Review?
• Plan Your Literature Review
• Identify a Research Gap
• Define Your Research Question
• Search the Literature
• Analyze Your Research Results
• Manage Research Results
• Write the Literature Review

What is a Literature Review?  What is its purpose?

The purpose of a literature review is to offer a  comprehensive review of scholarly literature on a specific topic along with an  evaluation of the strengths and weaknesses of authors' arguments . In other words, you are summarizing research available on a certain topic and then drawing conclusions about researchers' findings. To make gathering research easier, be sure to start with a narrow/specific topic and then widen your topic if necessary.

A thorough literature review provides an accurate description of current knowledge on a topic and identifies areas for future research.  Are there gaps or areas that require further study and exploration? What opportunities are there for further research? What is missing from my collection of resources? Are more resources needed?

It is important to note that conclusions described in the literature you gather may contradict each other completely or in part.  Recognize that knowledge creation is collective and cumulative.  Current research is built upon past research findings and discoveries.  Research may bring previously accepted conclusions into question.  A literature review presents current knowledge on a topic and may point out various academic arguments within the discipline.

What a Literature Review is not

• A literature review is not an annotated bibliography .  An annotated bibliography provides a brief summary, analysis, and reflection of resources included in the bibliography.  Often it is not a systematic review of existing research on a specific subject.  That said, creating an annotated bibliography throughout your research process may be helpful in managing the resources discovered through your research.
• A literature review is not a research paper .  A research paper explores a topic and uses resources discovered through the research process to support a position on the topic.  In other words, research papers present one side of an issue.  A literature review explores all sides of the research topic and evaluates all positions and conclusions achieved through the scientific research process even though some conclusions may conflict partially or completely.

From the Online Library

SAGE Research Methods is a web-based research methods tool that covers quantitative, qualitative and mixed methods. Researchers can explore methods and concepts to help design research projects, understand a particular method or identify a new method, and write up research. Sage Research Methods focuses on methodology rather than disciplines, and is of potential use to researchers from the social sciences, health sciences and other research areas.

• Sage Research Methods Project Planner - Reviewing the Literature View the resources and videos for a step-by-step guide to performing a literature review.

The Literature Review: Step by Step

Follow this step-by-step process by using the related tabs in this Guide.

• Define your Research question
• Analyze the material you’ve found
• Manage the results of your research
• Write your Review

Getting Started

Consider the following questions as you develop your research topic, conduct your research, and begin evaluating the resources discovered in the research process:

• What is known about the subject?
• Are there any gaps in the knowledge of the subject?
• Have areas of further study been identified by other researchers that you may want to consider?
• Who are the significant research personalities in this area?
• Is there consensus about the topic?
• What aspects have generated significant debate on the topic?
• What methods or problems were identified by others studying in the field and how might they impact your research?
• What is the most productive methodology for your research based on the literature you have reviewed?
• What is the current status of research in this area?
• What sources of information or data were identified that might be useful to you?
• How detailed? Will it be a review of ALL relevant material or will the scope be limited to more recent material, e.g., the last five years.
• Are you focusing on methodological approaches; on theoretical issues; on qualitative or quantitative research?

What is Academic Literature?

What is the difference between popular and scholarly literature?

To better understand the differences between popular and scholarly articles, comparing characteristics and purpose of the publications where these articles appear is helpful.

Popular Article (Magazine)

• Articles are shorter and are written for the general public
• General interest topics or current events are covered
• Language is simple and easy to understand
• Source material is not cited
• Articles often include glossy photographs, graphics, or visuals
• Articles are written by the publication's staff of journalists
• Articles are edited and information is fact checked

Examples of magazines that contain popular articles:

Scholarly Article (Academic Journal)

• Articles are written by scholars and researchers for academics, professionals, and experts in the field
• Articles are longer and report original research findings
• Topics are narrower in focus and provide in-depth analysis
• Technical or scholarly language is used
• Source material is cited
• Charts and graphs illustrating research findings are included
• Many are  "peer reviewed"  meaning that panels of experts review articles submitted for publication to ensure that proper research methods were used and research findings are contributing something new to the field before selecting for publication.

Examples of academic journals that contain scholarly articles:

Define your research question

Selecting a research topic can be overwhelming.  Consider following these steps:

1.  Brainstorm  research topic ideas

      - Free write: Set a timer for five minutes and write down as many ideas as you can in the allotted time

      -  Mind-Map  to explore how ideas are related

2.  Prioritize  topics based on personal interest and curiosity

3.  Pre-research

      - Explore encyclopedias and reference books for background information on the topic

      - Perform a quick database or Google search on the topic to explore current issues. 

4.  Focus the topic  by evaluating how much information is available on the topic

         - Too much information?  Consider narrowing the topic by focusing on a specific issue 

         - Too little information?  Consider broadening the topic 

5.  Determine your purpose  by considering whether your research is attempting to:

         - further the research on this topic

         - fill a gap in the research

         - support existing knowledge with new evidence

         - take a new approach or direction

         - question or challenge existing knowledge

6.  Finalize your research question

NOTE:  Be aware that your initial research question may change as you conduct research on your topic.

Searching the Literature

Research on your topic should be conducted in the academic literature.  The  Rasmussen University Online Library contains subject-focused databases that contain the leading academic journals in your programmatic area.

Consult the  Using the Online Library video tutorials  for information about how to effectively search library databases.

Watch the video below for tips on how to create a search statement that will provide relevant results

Need help starting your research?  Make a  research appointment with a Rasmussen Librarian .

TIP:  Document as you research.  Begin building your references list using the citation managers in one of these resources:

• APA Academic Writer
• NoodleTools

Recommended programmatic databases include:

Data Science

Coverage includes computer engineering, computer theory & systems, research and development, and the social and professional implications of new technologies. Articles come from more than 1,900 academic journals, trade magazines, and professional publications.

Provides access to full-text peer-reviewed journals, transactions, magazines, conference proceedings, and published standards in the areas of electrical engineering, computer science, and electronics. It also provides access to the IEEE Standards Dictionary Online. Full-text available.

Computing, telecommunications, art, science and design databases from ProQuest.

Healthcare Management

Articles from scholarly business journals back as far as 1886 with content from all disciplines of business, including marketing, management, accounting, management information systems, production and operations management, finance, and economics. Contains 55 videos from the Harvard Faculty Seminar Series, on topics such as leadership, sustaining competitive advantage, and globalization. To access the videos, click "More" in the blue bar at the top. Select "Images/ Business Videos." Uncheck "Image Quick View Collection" to indicate you only wish to search for videos. Enter search terms.

Provides a truly comprehensive business research collection. The collection consists of the following databases and more: ABI/INFORM Complete, ProQuest Entrepreneurship, ProQuest Accounting & Tax, International Bibliography of Social Sciences (IBSS), ProQuest Asian Business and Reference, and Banking Information Source.

The definitive research tool for all areas of nursing and allied health literature. Geared towards the needs of nurses and medical professionals. Covers more than 750 journals from 1937 to present.

HPRC provides information on the creation, implementation and study of health care policy and the health care system. Topics covered include health care administration, economics, planning, law, quality control, ethics, and more.

PolicyMap is an online mapping site that provides data on demographics, real estate, health, jobs, and other areas across the U.S. Access and visualize data from Census and third-party records.

Human Resources

Articles from all subject areas gathered from more than 11,000 magazines, journals, books and reports. Subjects include astronomy, multicultural studies, humanities, geography, history, law, pharmaceutical sciences, women's studies, and more. Coverage from 1887 to present. Start your research here.

Cochrane gathers and summarizes the best evidence from research to help you make informed choices about treatments. Whether a doctor or nurse, patient, researcher or student, Cochrane evidence provides a tool to enhance your healthcare knowledge and decision making on topics ranging from allergies, blood disorders, and cancer, to mental health, pregnancy, urology, and wounds.

Health sciences, biology, science, and pharmaceutical information from ProQuest. Includes articles from scholarly, peer-reviewed journals, practical and professional development content from professional journals, and general interest articles from magazines and newspapers.

Joanna Briggs Institute Academic Collection contains evidence-based information from across the globe, including evidence summaries, systematic reviews, best practice guidelines, and more. Subjects include medical, nursing, and healthcare specialties.

Comprehensive source of full-text articles from more than 1,450 scholarly medical journals.

Articles from more than 35 nursing journals in full text, searchable as far back as 1995.

Analyzing Your Research Results

You have completed your research and discovered many, many academic articles on your topic.  The next step involves evaluating and organizing the literature found in the research process.

As you review, keep in mind that there are three types of research studies:

• Quantitative
• Qualitative 
• Mixed Methods

Consider these questions as you review the articles you have gathered through the research process:

1. Does the study relate to your topic?

2. Were sound research methods used in conducting the study?

3. Does the research design fit the research question? What variables were chosen? Was the sample size adequate?

4. What conclusions were drawn?  Do the authors point out areas for further research?

Reading Academic Literature

Academic journals publish the results of research studies performed by experts in an academic discipline.  Articles selected for publication go through a rigorous peer-review process.  This process includes a thorough evaluation of the research submitted for publication by journal editors and other experts or peers in the field.  Editors select articles based on specific criteria including the research methods used, whether the research contributes new findings to the field of study, and how the research fits within the scope of the academic journal.  Articles selected often go through a revision process prior to publication.

Most academic journal articles include the following sections:

• Abstract    (An executive summary of the study)
• Introduction  (Definition of the research question to be studied)
• Literature Review  (A summary of past research noting where gaps exist)
• Methods  (The research design including variables, sample size, measurements)
• Data   (Information gathered through the study often displayed in tables and charts)
• Results   (Conclusions reached at the end of the study)
• Conclusion   (Discussion of whether the study proved the thesis; may suggest opportunities for further research)
• Bibliography  (A list of works cited in the journal article)

TIP:  To begin selecting articles for your research, read the   highlighted sections   to determine whether the academic journal article includes information relevant to your research topic.

Step 1: Skim the article

When sorting through multiple articles discovered in the research process, skimming through these sections of the article will help you determine whether the article will be useful in your research.

1.  Article title   and subject headings assigned to the article

2.   Abstract

3.   Introduction

4.  Conclusion

If the article fits your information need, go back and  read the article thoroughly.

TIP:  Create a folder on your computer to save copies of articles you plan to use in your thesis or research project.  Use  NoodleTools  or  APA Academic Writer  to save APA references.

Step 2: Determine Your Purpose

Think about how you will evaluate the academic articles you find and how you will determine whether to include them in your research project.  Ask yourself the following questions to focus your search in the academic literature:

• ​Are you looking for an overview of a topic? an explanation of a specific concept, idea, or position?
• Are you exploring gaps in the research to identify a new area for academic study?
• Are you looking for research that supports or disagrees with your thesis or research question?
• Are you looking for examples of a research design and/or research methods you are considering for your own research project?

Step 3: Read Critically

Before reading the article, ask yourself the following:

• What is my research question?  What position am I trying to support?
• What do I already know about this topic?  What do I need to learn?
• How will I evaluate the article?  Author's reputation? Research design? Treatment of topic? 
• What are my biases about the topic?

As you read the article make note of the following:

• Who is the intended audience for this article?
• What is the author's purpose in writing this article?
• What is the main point?
• How was the main point proven or supported?  
• Were scientific methods used in conducting the research?
• Do you agree or disagree with the author? Why?
• How does this article compare or connect with other articles on the topic?
• Does the author recommend areas for further study?
• How does this article help to answer your research question?

Managing your Research

Tip:  Create APA references for resources as you discover them in the research process

Use APA Academic Writer or NoodleTools to generate citations and manage your resources.  Find information on how to use these resources in the Citation Tools Guide .

Writing the Literature Review

Once research has been completed, it is time to structure the literature review and begin summarizing and synthesizing information.  The following steps may help with this process:

• Chronological
• By research method used
• Explore contradictory or conflicting conclusions
• Read each study critically
• Critique methodology, processes, and conclusions
• Consider how the study relates to your topic

• Description of public health nursing nutrition assessment and interventions for home‐visited women. This article provides a nice review of the literature in the article introduction. You can see how the authors have used the existing literature to make a case for their research questions. more... less... Horning, M. L., Olsen, J. M., Lell, S., Thorson, D. R., & Monsen, K. A. (2018). Description of public health nursing nutrition assessment and interventions for home‐visited women. Public Health Nursing, 35(4), 317–326. https://doi.org/10.1111/phn.12410
• Improving Diabetes Self-Efficacy in the Hispanic Population Through Self-Management Education Doctoral papers are a good place to see how literature reviews can be done. You can learn where they searched, what search terms they used, and how they decided which articles were included. Notice how the literature review is organized around the three main themes that came out of the literature search. more... less... Robles, A. N. (2023). Improving diabetes self-efficacy in the hispanic population through self-management education (Order No. 30635901). Available from ProQuest Dissertations & Theses Global: The Sciences and Engineering Collection. https://www.proquest.com/dissertations-theses/improving-diabetes-self-efficacy-hispanic/docview/2853708553/se-2
• Exploring mediating effects between nursing leadership and patient safety from a person-centred perspective: A literature review Reading articles that publish the results of a systematic literature review is a great way to see in detail how a literature review is conducted. These articles provide an article matrix, which provides you an example of how you can document information about the articles you find in your own search. To see more examples, include "literature review" or "systematic review" as a search term. more... less... Wang, M., & Dewing, J. (2021). Exploring mediating effects between nursing leadership and patient safety from a person‐centred perspective: A literature review. Journal of Nursing Management, 29(5), 878–889. https://doi.org/10.1111/jonm.13226
• Boolean Operators
• Keywords vs. Subjects
• Creating a Search String
• Library databases are collections of resources that are searchable, including full-text articles, books, and encyclopedias.
• Searching library databases is different than searching Google. Best results are achieved when using Keywords linked with Boolean Operators . 
• Applying Limiters such as full-text, publication date, resource type, language, geographic location, and subject help to refine search results.
• Utilizing Phrases or Fields , in addition to an awareness of Stop Words , can focus your search and retrieve more useful results.
• Have questions? Ask a Librarian

Boolean Operators connect keywords or concepts logically to retrieve relevant articles, books, and other resources.  There are three Boolean Operators:

Using AND 

• Narrows search results
• Connects two or more keywords/concepts
• All keywords/concepts connected with "and" must be in an article or resource to appear in the search results list

Venn diagram of the AND connector

Example: The result list will include resources that include both keywords -- "distracted driving" and "texting" -- in the same article or resource, represented in the shaded area where the circles intersect (area shaded in purple).

• Broadens search results ("OR means more!")
• Connects two or more synonyms or related keywords/concepts
• Resources appearing in the results list will include any of the terms connected with the OR connector

Venn diagram of the OR connector

Example:  The result list will include resources that include the keyword "texting" OR the keyword "cell phone" (entire area shaded in blue); either is acceptable.

• Excludes keywords or concepts from the search
• Narrows results by removing resources that contain the keyword or term connected with the NOT connector
• Use sparingly

Venn diagram of the NOT connector

Example: The result list will include all resources that include the term "car" (green area) but will exclude any resource that includes the term "motorcycle" (purple area) even though the term car may be present in the resource.

A library database searches for keywords throughout the entire resource record including the full-text of the resource, subject headings, tags, bibliographic information, etc.

• Natural language words or short phrases that describe a concept or idea
• Can retrieve too few or irrelevant results due to full-text searching (What words would an author use to write about this topic?)
• Provide flexibility in a search
• Must consider synonyms or related terms to improve search results
• TIP: Build a Keyword List

Example:  The keyword list above was developed to find resources that discuss how texting while driving results in accidents.  Notice that there are synonyms (texting and "text messaging"), related terms ("cell phones" and texting), and spelling variations ("cell phone" and cellphone).  Using keywords when searching full text requires consideration of various words that express an idea or concept.

• Subject Headings
• Predetermined "controlled vocabulary" database editors apply to resources to describe topical coverage of content
• Can retrieve more precise search results because every article assigned that subject heading will be retrieved.
• Provide less flexibility in a search
• Can be combined with a keyword search to focus search results.
• TIP: Consult database subject heading list or subject headings assigned to relevant resources

Example 1: In EBSCO's Academic Search Complete, clicking on the "Subject Terms" tab provides access to the entire subject heading list used in the database.  It also allows a search for specific subject terms.

Example 2:  A subject term can be incorporated into a keyword search by clicking on the down arrow next to "Select a Field" and selecting "Subject Terms" from the dropdown list.  Also, notice how subject headings are listed below the resource title, providing another strategy for discovering subject headings used in the database.

When a search term is more than one word, enclose the phrase in quotation marks to retrieve more precise and accurate results.  Using quotation marks around a term will search it as a "chunk," searching for those particular words together in that order within the text of a resource. 

"cell phone"

"distracted driving"

"car accident"

TIP: In some databases, neglecting to enclose phrases in quotation marks will insert the AND Boolean connector between each word resulting in unintended search results.

Truncation provides an option to search for a root of a keyword in order to retrieve resources that include variations of that word.  This feature can be used to broaden search results, although some results may not be relevant.  To truncate a keyword, type an asterisk (*) following the root of the word.

For example:

Library databases provide a variety of tools to limit and refine search results.  Limiters provide the ability to limit search results to resources having specified characteristics including:

• Resource type
• Publication date
• Geographic location

In both the EBSCO and ProQuest databases, the limiting tools are located in the left panel of the results page.

                                                 EBSCO                                                     ProQuest

The short video below provides a demonstration of how to use limiters to refine a list of search results.

Each resource in a library database is stored in a record.  In addition to the full-text of the resources, searchable Fields are attached that typically include:

• Journal title
• Date of Publication

Incorporating Fields into your search can assist in focusing and refining search results by limiting the results to those resources that include specific information in a particular field.

In both EBSCO and ProQuest databases, selecting the Advanced Search option will allow Fields to be included in a search.

For example, in the Advanced Search option in EBSCO's Academic Search Complete database, clicking on the down arrow next to "Select a Field" provides a list of fields that can be searched within that database.  Select the field and enter the information in the text box to the left to use this feature.

Stop words are short, commonly used words--articles, prepositions, and pronouns-- that are automatically dropped from a search.  Typical stop words include:

In library databases, a stop word will not be searched even if it is included in a phrase enclosed in quotation marks.  In some instances, a word will be substituted for the stop word to allow for the other words in the phrase to be searched in proximity to one another within the text of the resource.

For example, if you searched company of America, your result list will include these variatons:

• company in America
• company of America
• company for America

Creating an Search String

This short video demonstrates how to create a search string -- keywords connected with Boolean operators -- to use in a library database search to retrieve relevant resources for any research assignment.

• Database Search Menu Template Use this search menu template to plan a database search.
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• Volume 24, Issue 2
• Five tips for developing useful literature summary tables for writing review articles
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• http://orcid.org/0000-0003-0157-5319 Ahtisham Younas 1 , 2 ,
• http://orcid.org/0000-0002-7839-8130 Parveen Ali 3 , 4
• 1 Memorial University of Newfoundland , St John's , Newfoundland , Canada
• 2 Swat College of Nursing , Pakistan
• 3 School of Nursing and Midwifery , University of Sheffield , Sheffield , South Yorkshire , UK
• 4 Sheffield University Interpersonal Violence Research Group , Sheffield University , Sheffield , UK
• Correspondence to Ahtisham Younas, Memorial University of Newfoundland, St John's, NL A1C 5C4, Canada; ay6133{at}mun.ca

https://doi.org/10.1136/ebnurs-2021-103417

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Introduction

Literature reviews offer a critical synthesis of empirical and theoretical literature to assess the strength of evidence, develop guidelines for practice and policymaking, and identify areas for future research. 1 It is often essential and usually the first task in any research endeavour, particularly in masters or doctoral level education. For effective data extraction and rigorous synthesis in reviews, the use of literature summary tables is of utmost importance. A literature summary table provides a synopsis of an included article. It succinctly presents its purpose, methods, findings and other relevant information pertinent to the review. The aim of developing these literature summary tables is to provide the reader with the information at one glance. Since there are multiple types of reviews (eg, systematic, integrative, scoping, critical and mixed methods) with distinct purposes and techniques, 2 there could be various approaches for developing literature summary tables making it a complex task specialty for the novice researchers or reviewers. Here, we offer five tips for authors of the review articles, relevant to all types of reviews, for creating useful and relevant literature summary tables. We also provide examples from our published reviews to illustrate how useful literature summary tables can be developed and what sort of information should be provided.

Tip 1: provide detailed information about frameworks and methods

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Tabular literature summaries from a scoping review. Source: Rasheed et al . 3

The provision of information about conceptual and theoretical frameworks and methods is useful for several reasons. First, in quantitative (reviews synthesising the results of quantitative studies) and mixed reviews (reviews synthesising the results of both qualitative and quantitative studies to address a mixed review question), it allows the readers to assess the congruence of the core findings and methods with the adapted framework and tested assumptions. In qualitative reviews (reviews synthesising results of qualitative studies), this information is beneficial for readers to recognise the underlying philosophical and paradigmatic stance of the authors of the included articles. For example, imagine the authors of an article, included in a review, used phenomenological inquiry for their research. In that case, the review authors and the readers of the review need to know what kind of (transcendental or hermeneutic) philosophical stance guided the inquiry. Review authors should, therefore, include the philosophical stance in their literature summary for the particular article. Second, information about frameworks and methods enables review authors and readers to judge the quality of the research, which allows for discerning the strengths and limitations of the article. For example, if authors of an included article intended to develop a new scale and test its psychometric properties. To achieve this aim, they used a convenience sample of 150 participants and performed exploratory (EFA) and confirmatory factor analysis (CFA) on the same sample. Such an approach would indicate a flawed methodology because EFA and CFA should not be conducted on the same sample. The review authors must include this information in their summary table. Omitting this information from a summary could lead to the inclusion of a flawed article in the review, thereby jeopardising the review’s rigour.

Tip 2: include strengths and limitations for each article

Critical appraisal of individual articles included in a review is crucial for increasing the rigour of the review. Despite using various templates for critical appraisal, authors often do not provide detailed information about each reviewed article’s strengths and limitations. Merely noting the quality score based on standardised critical appraisal templates is not adequate because the readers should be able to identify the reasons for assigning a weak or moderate rating. Many recent critical appraisal checklists (eg, Mixed Methods Appraisal Tool) discourage review authors from assigning a quality score and recommend noting the main strengths and limitations of included studies. It is also vital that methodological and conceptual limitations and strengths of the articles included in the review are provided because not all review articles include empirical research papers. Rather some review synthesises the theoretical aspects of articles. Providing information about conceptual limitations is also important for readers to judge the quality of foundations of the research. For example, if you included a mixed-methods study in the review, reporting the methodological and conceptual limitations about ‘integration’ is critical for evaluating the study’s strength. Suppose the authors only collected qualitative and quantitative data and did not state the intent and timing of integration. In that case, the strength of the study is weak. Integration only occurred at the levels of data collection. However, integration may not have occurred at the analysis, interpretation and reporting levels.

Tip 3: write conceptual contribution of each reviewed article

While reading and evaluating review papers, we have observed that many review authors only provide core results of the article included in a review and do not explain the conceptual contribution offered by the included article. We refer to conceptual contribution as a description of how the article’s key results contribute towards the development of potential codes, themes or subthemes, or emerging patterns that are reported as the review findings. For example, the authors of a review article noted that one of the research articles included in their review demonstrated the usefulness of case studies and reflective logs as strategies for fostering compassion in nursing students. The conceptual contribution of this research article could be that experiential learning is one way to teach compassion to nursing students, as supported by case studies and reflective logs. This conceptual contribution of the article should be mentioned in the literature summary table. Delineating each reviewed article’s conceptual contribution is particularly beneficial in qualitative reviews, mixed-methods reviews, and critical reviews that often focus on developing models and describing or explaining various phenomena. Figure 2 offers an example of a literature summary table. 4

Tabular literature summaries from a critical review. Source: Younas and Maddigan. 4

Tip 4: compose potential themes from each article during summary writing

While developing literature summary tables, many authors use themes or subthemes reported in the given articles as the key results of their own review. Such an approach prevents the review authors from understanding the article’s conceptual contribution, developing rigorous synthesis and drawing reasonable interpretations of results from an individual article. Ultimately, it affects the generation of novel review findings. For example, one of the articles about women’s healthcare-seeking behaviours in developing countries reported a theme ‘social-cultural determinants of health as precursors of delays’. Instead of using this theme as one of the review findings, the reviewers should read and interpret beyond the given description in an article, compare and contrast themes, findings from one article with findings and themes from another article to find similarities and differences and to understand and explain bigger picture for their readers. Therefore, while developing literature summary tables, think twice before using the predeveloped themes. Including your themes in the summary tables (see figure 1 ) demonstrates to the readers that a robust method of data extraction and synthesis has been followed.

Tip 5: create your personalised template for literature summaries

Often templates are available for data extraction and development of literature summary tables. The available templates may be in the form of a table, chart or a structured framework that extracts some essential information about every article. The commonly used information may include authors, purpose, methods, key results and quality scores. While extracting all relevant information is important, such templates should be tailored to meet the needs of the individuals’ review. For example, for a review about the effectiveness of healthcare interventions, a literature summary table must include information about the intervention, its type, content timing, duration, setting, effectiveness, negative consequences, and receivers and implementers’ experiences of its usage. Similarly, literature summary tables for articles included in a meta-synthesis must include information about the participants’ characteristics, research context and conceptual contribution of each reviewed article so as to help the reader make an informed decision about the usefulness or lack of usefulness of the individual article in the review and the whole review.

In conclusion, narrative or systematic reviews are almost always conducted as a part of any educational project (thesis or dissertation) or academic or clinical research. Literature reviews are the foundation of research on a given topic. Robust and high-quality reviews play an instrumental role in guiding research, practice and policymaking. However, the quality of reviews is also contingent on rigorous data extraction and synthesis, which require developing literature summaries. We have outlined five tips that could enhance the quality of the data extraction and synthesis process by developing useful literature summaries.

• Aromataris E ,
• Rasheed SP ,

Twitter @Ahtisham04, @parveenazamali

Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Competing interests None declared.

Patient consent for publication Not required.

Provenance and peer review Not commissioned; externally peer reviewed.

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How to Write a Literature Review

What is a literature review.

• What Is the Literature
• Writing the Review

A literature review is much more than an annotated bibliography or a list of separate reviews of articles and books. It is a critical, analytical summary and synthesis of the current knowledge of a topic. Thus it should compare and relate different theories, findings, etc, rather than just summarize them individually. In addition, it should have a particular focus or theme to organize the review. It does not have to be an exhaustive account of everything published on the topic, but it should discuss all the significant academic literature and other relevant sources important for that focus.

This is meant to be a general guide to writing a literature review: ways to structure one, what to include, how it supplements other research. For more specific help on writing a review, and especially for help on finding the literature to review, sign up for a Personal Research Session .

The specific organization of a literature review depends on the type and purpose of the review, as well as on the specific field or topic being reviewed. But in general, it is a relatively brief but thorough exploration of past and current work on a topic. Rather than a chronological listing of previous work, though, literature reviews are usually organized thematically, such as different theoretical approaches, methodologies, or specific issues or concepts involved in the topic. A thematic organization makes it much easier to examine contrasting perspectives, theoretical approaches, methodologies, findings, etc, and to analyze the strengths and weaknesses of, and point out any gaps in, previous research. And this is the heart of what a literature review is about. A literature review may offer new interpretations, theoretical approaches, or other ideas; if it is part of a research proposal or report it should demonstrate the relationship of the proposed or reported research to others' work; but whatever else it does, it must provide a critical overview of the current state of research efforts. 

Literature reviews are common and very important in the sciences and social sciences. They are less common and have a less important role in the humanities, but they do have a place, especially stand-alone reviews.

Types of Literature Reviews

There are different types of literature reviews, and different purposes for writing a review, but the most common are:

• Stand-alone literature review articles . These provide an overview and analysis of the current state of research on a topic or question. The goal is to evaluate and compare previous research on a topic to provide an analysis of what is currently known, and also to reveal controversies, weaknesses, and gaps in current work, thus pointing to directions for future research. You can find examples published in any number of academic journals, but there is a series of Annual Reviews of *Subject* which are specifically devoted to literature review articles. Writing a stand-alone review is often an effective way to get a good handle on a topic and to develop ideas for your own research program. For example, contrasting theoretical approaches or conflicting interpretations of findings can be the basis of your research project: can you find evidence supporting one interpretation against another, or can you propose an alternative interpretation that overcomes their limitations?
• Part of a research proposal . This could be a proposal for a PhD dissertation, a senior thesis, or a class project. It could also be a submission for a grant. The literature review, by pointing out the current issues and questions concerning a topic, is a crucial part of demonstrating how your proposed research will contribute to the field, and thus of convincing your thesis committee to allow you to pursue the topic of your interest or a funding agency to pay for your research efforts.
• Part of a research report . When you finish your research and write your thesis or paper to present your findings, it should include a literature review to provide the context to which your work is a contribution. Your report, in addition to detailing the methods, results, etc. of your research, should show how your work relates to others' work.

A literature review for a research report is often a revision of the review for a research proposal, which can be a revision of a stand-alone review. Each revision should be a fairly extensive revision. With the increased knowledge of and experience in the topic as you proceed, your understanding of the topic will increase. Thus, you will be in a better position to analyze and critique the literature. In addition, your focus will change as you proceed in your research. Some areas of the literature you initially reviewed will be marginal or irrelevant for your eventual research, and you will need to explore other areas more thoroughly. 

Examples of Literature Reviews

See the series of Annual Reviews of *Subject* which are specifically devoted to literature review articles to find many examples of stand-alone literature reviews in the biomedical, physical, and social sciences. 

Research report articles vary in how they are organized, but a common general structure is to have sections such as:

• Abstract - Brief summary of the contents of the article
• Introduction - A explanation of the purpose of the study, a statement of the research question(s) the study intends to address
• Literature review - A critical assessment of the work done so far on this topic, to show how the current study relates to what has already been done
• Methods - How the study was carried out (e.g. instruments or equipment, procedures, methods to gather and analyze data)
• Results - What was found in the course of the study
• Discussion - What do the results mean
• Conclusion - State the conclusions and implications of the results, and discuss how it relates to the work reviewed in the literature review; also, point to directions for further work in the area

Here are some articles that illustrate variations on this theme. There is no need to read the entire articles (unless the contents interest you); just quickly browse through to see the sections, and see how each section is introduced and what is contained in them.

The Determinants of Undergraduate Grade Point Average: The Relative Importance of Family Background, High School Resources, and Peer Group Effects , in The Journal of Human Resources , v. 34 no. 2 (Spring 1999), p. 268-293.

This article has a standard breakdown of sections:

• Introduction
• Literature Review
• Some discussion sections

First Encounters of the Bureaucratic Kind: Early Freshman Experiences with a Campus Bureaucracy , in The Journal of Higher Education , v. 67 no. 6 (Nov-Dec 1996), p. 660-691.

This one does not have a section specifically labeled as a "literature review" or "review of the literature," but the first few sections cite a long list of other sources discussing previous research in the area before the authors present their own study they are reporting.

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• Last Updated: Jan 11, 2024 9:48 AM
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How to Write a Literature Review

• 6. Synthesize
• Literature Reviews: A Recap
• Reading Journal Articles
• Does it Describe a Literature Review?
• 1. Identify the Question
• 2. Review Discipline Styles
• Searching Article Databases
• Finding Full-Text of an Article
• Citation Chaining
• When to Stop Searching
• 4. Manage Your References
• 5. Critically Analyze and Evaluate

Synthesis Visualization

Synthesis matrix example.

• 7. Write a Literature Review

• Synthesis Worksheet

About Synthesis

Approaches to Synthesis

You can sort the literature in various ways, for example:

How to Begin?

Read your sources carefully and find the main idea(s) of each source

Look for similarities in your sources – which sources are talking about the same main ideas? (for example, sources that discuss the historical background on your topic)

Use the worksheet (above) or synthesis matrix (below) to get organized

This work can be messy. Don't worry if you have to go through a few iterations of the worksheet or matrix as you work on your lit review!

Four Examples of Student Writing

In the four examples below, only ONE shows a good example of synthesis: the fourth column, or  Student D . For a web accessible version, click the link below the image.

Long description of "Four Examples of Student Writing" for web accessibility

• Download a copy of the "Four Examples of Student Writing" chart

Click on the example to view the pdf.

From Jennifer Lim

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