The effect of chronic caffeine supplementation on endurance performance has been studied extensively in different populations. However, concurrent research on the effects of acute supplementation of caffeine on cardiorespiratory responses during endurance exercise in hot and humid conditions is unavailable
Source: Ping, WC, Keong, CC & Bandyopadhyay, A 2010, ‘Effects of acute supplementation of caffeine on cardiorespiratory responses during endurance running in a hot and humid climate’, Indian Journal of Medical Research, vol. 132, pp. 36–41. Used under a CC-BY-NC-SA licence.
Step two of writing a literature review is synthesis.
Synthesis describes combining separate components or elements to form a connected whole.
You will use the results of your analysis to find themes to build your literature review around. Each of the themes identified will become a subheading within the body of your literature review.
A good place to start when identifying themes is with the dependent variables (results/findings) that were investigated in the research studies.
Because all of the research articles you are incorporating into your literature review are related to your topic, it is likely that they have similar study designs and have measured similar dependent variables. Review the ‘Results’ column of your analysis grid. You may like to collate the common themes in a synthesis grid (see, for example Table 7.4 ).
Step three of writing a literature review is evaluation, which can only be done after carefully analysing your research papers and synthesising the common themes (findings).
During the evaluation stage, you are making judgements on the themes presented in the research articles that you have read. This includes providing physiological explanations for the findings. It may be useful to refer to the discussion section of published original investigation research papers, or another literature review, where the authors may mention tested or hypothetical physiological mechanisms that may explain their findings.
When the findings of the investigations related to a particular theme are inconsistent (e.g., one study shows that caffeine effects performance and another study shows that caffeine had no effect on performance) you should attempt to provide explanations of why the results differ, including physiological explanations. A good place to start is by comparing the methodologies to determine if there are any differences that may explain the differences in the findings (see the ‘Experimental design’ column of your analysis grid). An example of evaluation is shown in the examples that follow in this section, under ‘Running performance’ and ‘RPE ratings’.
When the findings of the papers related to a particular theme are consistent (e.g., caffeine had no effect on oxygen uptake in both studies) an evaluation should include an explanation of why the results are similar. Once again, include physiological explanations. It is still a good idea to compare methodologies as a background to the evaluation. An example of evaluation is shown in the following under ‘Oxygen consumption’.
Once you have completed the analysis, and synthesis grids and written your evaluation of the research papers , you can combine synthesis and evaluation information to create a paragraph for a literature review ( Figure 7.4 ).
The following paragraphs are an example of combining the outcome of the synthesis and evaluation stages to produce a paragraph for a literature review.
Note that this is an example using only two papers – most literature reviews would be presenting information on many more papers than this ( (e.g., 106 papers in the review article by Bain and colleagues discussed later in this chapter). However, the same principle applies regardless of the number of papers reviewed.
The next part of this chapter looks at the each section of a literature review and explains how to write them by referring to a review article that was published in Frontiers in Physiology and shown in Figure 7.1. Each section from the published article is annotated to highlight important features of the format of the review article, and identifies the synthesis and evaluation information.
In the examination of each review article section we will point out examples of how the authors have presented certain information and where they display application of important cognitive processes; we will use the colour code shown below:
This should be one paragraph that accurately reflects the contents of the review article.
The introduction should establish the context and importance of the review
The reference section provides a list of the references that you cited in the body of your review article. The format will depend on the journal of publication as each journal has their own specific referencing format.
It is important to accurately cite references in research papers to acknowledge your sources and ensure credit is appropriately given to authors of work you have referred to. An accurate and comprehensive reference list also shows your readers that you are well-read in your topic area and are aware of the key papers that provide the context to your research.
It is important to keep track of your resources and to reference them consistently in the format required by the publication in which your work will appear. Most scientists will use reference management software to store details of all of the journal articles (and other sources) they use while writing their review article. This software also automates the process of adding in-text references and creating a reference list. In the review article by Bain et al. (2014) used as an example in this chapter, the reference list contains 106 items, so you can imagine how much help referencing software would be. Chapter 5 shows you how to use EndNote, one example of reference management software.
Click the drop down below to review the terms learned from this chapter.
Copyright note:
Bain, A.R., Morrison, S.A., & Ainslie, P.N. (2014). Cerebral oxygenation and hyperthermia. Frontiers in Physiology, 5 , 92.
Pautasso, M. (2013). Ten simple rules for writing a literature review. PLoS Computational Biology, 9 (7), e1003149.
How To Do Science Copyright © 2022 by University of Southern Queensland is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.
Reference management. Clean and simple.
How to write a literature review, 1. determine the purpose of your literature review, 2. do an extensive search, 3. evaluate and select literature, 4. analyze the literature, 5. plan the structure of your literature review, 6. write your literature review, other resources to help you write a successful literature review, frequently asked questions about writing a literature review, related articles.
A literature review is an assessment of the sources in a chosen topic of research.
A good literature review does not just summarize sources. It analyzes the state of the field on a given topic and creates a scholarly foundation for you to make your own intervention. It demonstrates to your readers how your research fits within a larger field of study.
In a thesis, a literature review is part of the introduction, but it can also be a separate section. In research papers, a literature review may have its own section or it may be integrated into the introduction, depending on the field.
➡️ Our guide on what is a literature review covers additional basics about literature reviews.
In this section, we review each step of the process of creating a literature review.
In the first step, make sure you know specifically what the assignment is and what form your literature review should take. Read your assignment carefully and seek clarification from your professor or instructor if needed. You should be able to answer the following questions:
In addition to that, be aware that the narrower your topic, the easier it will be to limit the number of sources you need to read in order to get a good overview of the topic.
Now you need to find out what has been written on the topic and search for literature related to your research topic. Make sure to select appropriate source material, which means using academic or scholarly sources , including books, reports, journal articles , government documents and web resources.
➡️ If you’re unsure about how to tell if a source is scholarly, take a look at our guide on how to identify a scholarly source .
Come up with a list of relevant keywords and then start your search with your institution's library catalog, and extend it to other useful databases and academic search engines like:
➡️ Our guide on how to collect data for your thesis might be helpful at this stage of your research as well as the top list of academic search engines .
Once you find a useful article, check out the reference list. It should provide you with even more relevant sources. Also, keep a note of the:
Keeping track of the bibliographic information for each source will save you time when you’re ready to create citations. You could also use a reference manager like Paperpile to automatically save, manage, and cite your references.
Read the literature. You will most likely not be able to read absolutely everything that is out there on the topic. Therefore, read the abstract first to determine whether the rest of the source is worth your time. If the source is relevant for your topic:
Now you are ready to analyze the literature you have gathered. While your are working on your analysis, you should ask the following questions:
Tip: Decide on the structure of your literature review before you start writing.
There are various ways to organize your literature review:
Regardless of the structure you chose, a review should always include the following three sections:
➡️ If your literature review is part of a longer paper, visit our guide on what is a research paper for additional tips.
➡️ UNC writing center: Literature reviews
➡️ How to write a literature review in 3 steps
➡️ How to write a literature review in 30 minutes or less
The goal of a literature review is to asses the state of the field on a given topic in preparation for making an intervention.
A literature review should have its own independent section. You should indicate clearly in the table of contents where it can be found, and address this section as “Literature Review.”
There is no set amount of words for a literature review; the length depends on the research. If you are working with a large amount of sources, then it will be long. If your paper does not depend entirely on references, then it will be short.
Most research papers include a literature review. By assessing the available sources in your field of research, you will be able to make a more confident argument about the topic.
Literature reviews are most commonly found in theses and dissertations. However, you find them in research papers as well.
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Before you begin writing your paper, you will need to decide upon a way to organize your information. You can organize your paper using a number of different strategies, such as the following:
When literature reviews are incorporated into a research paper, they are often structured using the funnel method , which begins with a broad overview of a topic and then narrows down to more specific themes before focusing in on the specific research question that the paper will address.
A literature review paper often follows this basic organization:
Introduction
A literature review paper not only describes and evaluates the scholarly research literature related to a particular topic, but it also synthesizes that information. Synthesis is the process of weaving together information from sources to arrive at new analyses and insights.
To help you prepare to synthesize sources in your paper, you can take the topic matrix that you prepared as you were organizing your sources, and flesh it out into a synthesis matrix that contains detailed notes from each source as they relate to different topics and subtopics of your literature review. Once you've completed your synthesis matrix, you can more easily identify ways that sources relate to each other in terms of their similarities and differences, methodological strengths and weakness, and contradictions and gaps. The video below shows how to create a synthesis matrix.
Video: Synthesis Matrix Tutorial by Andrew Davis .
A literature review paper should flow logically from one topic to the next. As you write your paper, consider these tips:
Literature review.
Reviewing the Literature: Why do it?
Literature reviews vary; there are many ways to write a literature review based on discipline, material type, and other factors.
Background:
Where to get help (there are lots of websites, blogs , articles, and books on this topic) :
READ related material and pay attention to how others write their literature reviews:
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Nowadays, there is a huge demand for scientific literature reviews as they are especially appreciated by scholars or researchers when designing their research proposals. While finding information is less of a problem to them, discerning which paper or publication has enough quality has become one of the biggest issues. Literature reviews narrow the current knowledge on a certain field and examine the latest publications’ strengths and weaknesses. This way, they are priceless tools not only for those who are starting their research, but also for all those interested in recent publications. To be useful, literature reviews must be written in a professional way with a clear structure. The amount of work needed to write a scientific literature review must be considered before starting one since the tasks required can overwhelm many if the working method is not the best.
Writing a scientific review implies both researching for relevant academic content and writing , however, writing without having a clear objective is a common mistake. Sometimes, studying the situation and defining the work’s system is so important and takes equally as much time as that required in writing the final result. Therefore, we suggest that you divide your path into three steps.
Think about your target and narrow down your topic. If you don’t choose a well-defined topic, you can find yourself dealing with a wide subject and plenty of publications about it. Remember that researchers usually deal with really specific fields of study.
It is time to be a critic and locate only pertinent publications. While researching for content consider publications that were written 3 years ago at the most. Write notes and summarize the content of each paper as that will help you in the next step.
Check some literature review examples to decide how to start writing a good literature review . When your goals and structure are defined, begin writing without forgetting your target at any moment.
Related: Conducting a literature survey? Wish to learn more about scientific misconduct? Check out this resourceful infographic.
Here you have a to-do list to help you write your review :
Scholars and researchers are usually the best candidates to write scientific literature reviews, not only because they are experts in a certain field, but also because they know the exigencies and needs that researchers have while writing research proposals or looking for information among thousands of academic papers. Therefore, considering your experience as a researcher can help you understand how to write a scientific literature review.
Have you faced challenges while drafting your first literature review? How do you think can these tips help you in acing your next literature review? Let us know in the comments section below! You can also visit our Q&A forum for frequently asked questions related to copyrights answered by our team that comprises eminent researchers and publication experts.
Thank you for your information. It adds knowledge on critical review being a first time to do it, it helps a lot.
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Scientific review articles are comprehensive, focused reviews of the scientific literature written by subject matter experts. The task of writing a scientific review article can seem overwhelming; however, it can be managed by using an organized approach and devoting sufficient time to the process. The process involves selecting a topic about which the authors are knowledgeable and enthusiastic, conducting a literature search and critical analysis of the literature, and writing the article, which is composed of an abstract, introduction, body, and conclusion, with accompanying tables and figures. This article, which focuses on the narrative or traditional literature review, is intended to serve as a guide with practical steps for new writers. Tips for success are also discussed, including selecting a focused topic, maintaining objectivity and balance while writing, avoiding tedious data presentation in a laundry list format, moving from descriptions of the literature to critical analysis, avoiding simplistic conclusions, and budgeting time for the overall process.
Keywords: manuscript; research; scientific review article; writing.
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1. identify how and why the research was carried out, 2. establish the research context, 3. evaluate the research, 4. establish the significance of the research.
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Read the article(s) carefully and use the questions below to help you identify how and why the research was carried out. Look at the following sections:
These questions were adapted from the following sources: Kuyper, B.J. (1991). Bringing up scientists in the art of critiquing research. Bioscience 41(4), 248-250. Wood, J.M. (2003). Research Lab Guide. MICR*3260 Microbial Adaptation and Development Web Site . Retrieved July 31, 2006.
Once you are familiar with the article, you can establish the research context by asking the following questions:
These questions were adapted from the following sources: Kuyper, B.J. (1991). Bringing up scientists in the art of critiquing research. Bioscience 41(4), 248-250. Wood, J.M. (2003). Research Lab Guide. MICR*3260 Microbial Adaptation and Development Web Site . Retrieved July 31, 2006.
Remember that simply disagreeing with the material is not considered to be a critical assessment of the material. For example, stating that the sample size is insufficient is not a critical assessment. Describing why the sample size is insufficient for the claims being made in the study would be a critical assessment.
Use the questions below to help you evaluate the quality of the authors’ research:
These questions were adapted from the following sources: Kuyper, B.J. (1991). Bringing up scientists in the art of critiquing research. Bioscience 41(4), 248-250. Wood, J.M. (2003). Research Lab Guide. MICR*3260 Microbial Adaptation and Development Web Site. Retrieved July 31, 2006.
After you have evaluated the research, consider whether the research has been successful. Has it led to new questions being asked, or new ways of using existing knowledge? Are other researchers citing this paper?
You should consider the following questions:
To answer these questions, look at review articles to find out how reviewers view this piece of research. Look at research articles and databases like Web of Science to see how other people have used this work. What range of journals have cited this article?
These questions were adapted from the following sources:
Kuyper, B.J. (1991). Bringing up scientists in the art of critiquing research. Bioscience 41(4), 248-250. Wood, J.M. (2003). Research Lab Guide. MICR*3260 Microbial Adaptation and Development Web Site . Retrieved July 31, 2006.
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In the medical sciences, the importance of review articles is rising. When clinicians want to update their knowledge and generate guidelines about a topic, they frequently use reviews as a starting point. The value of a review is associated with what has been done, what has been found and how these findings are presented. Before asking ‘how,’ the question of ‘why’ is more important when starting to write a review. The main and fundamental purpose of writing a review is to create a readable synthesis of the best resources available in the literature for an important research question or a current area of research. Although the idea of writing a review is attractive, it is important to spend time identifying the important questions. Good review methods are critical because they provide an unbiased point of view for the reader regarding the current literature. There is a consensus that a review should be written in a systematic fashion, a notion that is usually followed. In a systematic review with a focused question, the research methods must be clearly described. A ‘methodological filter’ is the best method for identifying the best working style for a research question, and this method reduces the workload when surveying the literature. An essential part of the review process is differentiating good research from bad and leaning on the results of the better studies. The ideal way to synthesize studies is to perform a meta-analysis. In conclusion, when writing a review, it is best to clearly focus on fixed ideas, to use a procedural and critical approach to the literature and to express your findings in an attractive way.
The importance of review articles in health sciences is increasing day by day. Clinicians frequently benefit from review articles to update their knowledge in their field of specialization, and use these articles as a starting point for formulating guidelines. [ 1 , 2 ] The institutions which provide financial support for further investigations resort to these reviews to reveal the need for these researches. [ 3 ] As is the case with all other researches, the value of a review article is related to what is achieved, what is found, and the way of communicating this information. A few studies have evaluated the quality of review articles. Murlow evaluated 50 review articles published in 1985, and 1986, and revealed that none of them had complied with clear-cut scientific criteria. [ 4 ] In 1996 an international group that analyzed articles, demonstrated the aspects of review articles, and meta-analyses that had not complied with scientific criteria, and elaborated QUOROM (QUality Of Reporting Of Meta-analyses) statement which focused on meta-analyses of randomized controlled studies. [ 5 ] Later on this guideline was updated, and named as PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). [ 6 ]
Review articles are divided into 2 categories as narrative, and systematic reviews. Narrative reviews are written in an easily readable format, and allow consideration of the subject matter within a large spectrum. However in a systematic review, a very detailed, and comprehensive literature surveying is performed on the selected topic. [ 7 , 8 ] Since it is a result of a more detailed literature surveying with relatively lesser involvement of author’s bias, systematic reviews are considered as gold standard articles. Systematic reviews can be diivded into qualitative, and quantitative reviews. In both of them detailed literature surveying is performed. However in quantitative reviews, study data are collected, and statistically evaluated (ie. meta-analysis). [ 8 ]
Before inquring for the method of preparation of a review article, it is more logical to investigate the motivation behind writing the review article in question. The fundamental rationale of writing a review article is to make a readable synthesis of the best literature sources on an important research inquiry or a topic. This simple definition of a review article contains the following key elements:
For the specification of important questions to be answered, number of literature references to be consulted should be more or less determined. Discussions should be conducted with colleagues in the same area of interest, and time should be reserved for the solution of the problem(s). Though starting to write the review article promptly seems to be very alluring, the time you spend for the determination of important issues won’t be a waste of time. [ 9 ]
The PRISMA statement [ 6 ] elaborated to write a well-designed review articles contains a 27-item checklist ( Table 1 ). It will be reasonable to fulfill the requirements of these items during preparation of a review article or a meta-analysis. Thus preparation of a comprehensible article with a high-quality scientific content can be feasible.
PRISMA statement: A 27-item checklist
Title | ||
Title | 1 Identify the article as a systematic review, meta-analysis, or both | |
Summary | ||
Structured summary | 2 Write a structured summary including, as applicable, background; objectives; data sources; study eligibility criteria, participants, treatments, study appraisal and synthesis methods; results; limitations; conclusions and implications of key findings; and systematic review registration number | |
Introduction | ||
Rationale | 3 Explain the rationale for the review in the context of what is already known | |
Objectives | 4 Provide an explicit statement of questions being addressed with reference to participants, interventions, comparisons, outcomes, and study design (PICOS) | |
Methods | ||
Protocol and registration | 5 Indicate if a review protocol exists, if and where it can be accessed (such as a web address), and, if available, provide registration information including the registration number | |
Eligibility criteria | 6 Specify study characteristics (such as PICOS, length of follow-up) and report characteristics (such as years considered, language, publication status) used as criteria for eligibility, giving rationale | |
Sources of Information | 7 Describe all information sources in the survey (such as databases with dates of coverage, contact with study authors to identify additional studies) and date last searched | |
Survey | 8 Present the full electronic search strategy for at least one major database, including any limits used, such that it could be repeated | |
Study selection | 9 State the process for selecting studies (that is, for screening, for determining eligibility, for inclusion in the systematic review, and, if applicable, for inclusion in the meta-analysis) | |
Data collection process | 10 Describe the method of data extraction from reports (such as piloted forms, independently by two reviewers) and any processes for obtaining and confirming data from investigators | |
Data items | 11 List and define all variables for which data were sought (such as PICOS, funding sources) and any assumptions and simplifications made | |
Risk of bias in individual studies | 12 Describe methods used for assessing risk of bias in individual studies (including specification of whether this was done at the study or outcome level, or both), and how this information is to be used in any data synthesis | |
Summary measures | 13 State the principal summary measures (such as risk ratio, difference in means) | |
Synthesis of outcomes | 14 For each meta-analysis, explain methods of data use, and combination methods of study outcomes, and if done consistency measurements should be indicated (ie P test) | |
Risk of bias across studies | 15 Specify any assessment of risk of bias that may affect the cumulative evidence (such as publication bias, selective reporting within studies). | |
Additional analyses | 16 Describe methods of additional analyses (such as sensitivity or subgroup analyses, meta-regression), if done, indicating which were pre-specified. | |
Results | ||
Study selection | 17 Give numbers of studies screened, assessed for eligibility, and included in the review, with reasons for exclusions at each stage, ideally with a flow diagram. | |
Study characteristics | 18 For each study, present characteristics for which data were extracted (such as study size, PICOS, follow-up period) and provide the citation. | |
Risk of bias within studies | 19 Present data on risk of bias of each study and, if available, any outcome-level assessment (see item 12) | |
Results of individual studies | 20 For all outcomes considered (benefits and harms), present, for each study, simple summary data for each intervention group and effect estimates and confidence intervals, ideally with a forest plot (a type of graph used in meta-analyses which demonstrates relat, ve success rates of treatment outcomes of multiple scientific studies analyzing the same topic) | |
Syntheses of resxults | 21 Present the results of each meta-analyses including confidence intervals and measures of consistency | |
Risk of bias across studies | 22 Present results of any assessment of risk of bias across studies (see item 15). | |
Additional analyses | 23 Give results of additional analyses, if done such as sensitivity or subgroup analyses, meta-regression (see item 16) | |
Discussion | ||
Summary of evidence | 24 Summarize the main findings, including the strength of evidence for each main outcome; consider their relevance to key groups (such as healthcare providers, users, and policy makers) | |
Limitations | 25 Discuss limitations at study and outcome level (such as risk of bias), and at review level such as incomplete retrieval of identified research, reporting bias | |
Conclusions | 26 Provide a general interpretation of the results in the context of other evidence, and implications for future research | |
Funding | ||
Funding | 27 Indicate sources of funding or other support (such as supply of data) for the systematic review, and the role of funders for the systematic review |
Important differences exist between systematic, and non-systematic reviews which especially arise from methodologies used in the description of the literature sources. A non-systematic review means use of articles collected for years with the recommendations of your colleagues, while systematic review is based on struggles to search for, and find the best possible researches which will respond to the questions predetermined at the start of the review.
Though a consensus has been reached about the systematic design of the review articles, studies revealed that most of them had not been written in a systematic format. McAlister et al. analyzed review articles in 6 medical journals, and disclosed that in less than one fourth of the review articles, methods of description, evaluation or synthesis of evidence had been provided, one third of them had focused on a clinical topic, and only half of them had provided quantitative data about the extend of the potential benefits. [ 10 ]
Use of proper methodologies in review articles is important in that readers assume an objective attitude towards updated information. We can confront two problems while we are using data from researches in order to answer certain questions. Firstly, we can be prejudiced during selection of research articles or these articles might be biased. To minimize this risk, methodologies used in our reviews should allow us to define, and use researches with minimal degree of bias. The second problem is that, most of the researches have been performed with small sample sizes. In statistical methods in meta-analyses, available researches are combined to increase the statistical power of the study. The problematic aspect of a non-systematic review is that our tendency to give biased responses to the questions, in other words we apt to select the studies with known or favourite results, rather than the best quality investigations among them.
As is the case with many research articles, general format of a systematic review on a single subject includes sections of Introduction, Methods, Results, and Discussion ( Table 2 ).
Structure of a systematic review
Introduction | Presents the problem and certain issues dealt in the review article |
Methods | Describes research, and evaluation process Specifies the number of studies evaluated orselected |
Results | Describes the quality, and outcomes of the selected studies |
Discussion | Summarizes results, limitations, and outcomes of the procedure and research |
Steps, and targets of constructing a good review article are listed in Table 3 . To write a good review article the items in Table 3 should be implemented step by step. [ 11 – 13 ]
Steps of a systematic review
Formulation of researchable questions | Select answerable questions |
Disclosure of studies | Databases, and key words |
Evaluation of its quality | Quality criteria during selection of studies |
Synthesis | Methods interpretation, and synthesis of outcomes |
It might be helpful to divide the research question into components. The most prevalently used format for questions related to the treatment is PICO (P - Patient, Problem or Population; I-Intervention; C-appropriate Comparisons, and O-Outcome measures) procedure. For example In female patients (P) with stress urinary incontinence, comparisons (C) between transobturator, and retropubic midurethral tension-free band surgery (I) as for patients’ satisfaction (O).
In a systematic review on a focused question, methods of investigation used should be clearly specified.
Ideally, research methods, investigated databases, and key words should be described in the final report. Different databases are used dependent on the topic analyzed. In most of the clinical topics, Medline should be surveyed. However searching through Embase and CINAHL can be also appropriate.
While determining appropriate terms for surveying, PICO elements of the issue to be sought may guide the process. Since in general we are interested in more than one outcome, P, and I can be key elements. In this case we should think about synonyms of P, and I elements, and combine them with a conjunction AND.
One method which might alleviate the workload of surveying process is “methodological filter” which aims to find the best investigation method for each research question. A good example of this method can be found in PubMed interface of Medline. The Clinical Queries tool offers empirically developed filters for five different inquiries as guidelines for etiology, diagnosis, treatment, prognosis or clinical prediction.
As an indispensable component of the review process is to discriminate good, and bad quality researches from each other, and the outcomes should be based on better qualified researches, as far as possible. To achieve this goal you should know the best possible evidence for each type of question The first component of the quality is its general planning/design of the study. General planning/design of a cohort study, a case series or normal study demonstrates variations.
A hierarchy of evidence for different research questions is presented in Table 4 . However this hierarchy is only a first step. After you find good quality research articles, you won’t need to read all the rest of other articles which saves you tons of time. [ 14 ]
Determination of levels of evidence based on the type of the research question
I | Systematic review of Level II studies | Systematic review of Level II studies | Systematic review of Level II studies | Systematic review of Level II studies |
II | Randomized controlled study | Crross-sectional study in consecutive patients | Initial cohort study | Prospective cohort study |
III | One of the following: Non-randomized experimental study (ie. controlled pre-, and post-test intervention study) Comparative studies with concurrent control groups (observational study) (ie. cohort study, case-control study) | One of the following: Cross-sectional study in non-consecutive case series; diagnostic case-control study | One of the following: Untreated control group patients in a randomized controlled study, integrated cohort study | One of the following: Retrospective cohort study, case-control study (Note: these are most prevalently used types of etiological studies; for other alternatives, and interventional studies see Level III |
IV | Case series | Case series | Case series or cohort studies with patients at different stages of their disease states |
Rarely all researches arrive at the same conclusion. In this case a solution should be found. However it is risky to make a decision based on the votes of absolute majority. Indeed, a well-performed large scale study, and a weakly designed one are weighed on the same scale. Therefore, ideally a meta-analysis should be performed to solve apparent differences. Ideally, first of all, one should be focused on the largest, and higher quality study, then other studies should be compared with this basic study.
In conclusion, during writing process of a review article, the procedures to be achieved can be indicated as follows: 1) Get rid of fixed ideas, and obsessions from your head, and view the subject from a large perspective. 2) Research articles in the literature should be approached with a methodological, and critical attitude and 3) finally data should be explained in an attractive way.
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Literature reviews are in great demand in most scientific fields. Their need stems from the ever-increasing output of scientific publications .For example, compared to 1991, in 2008 three, eight, and forty times more papers were indexed in Web of Science on malaria, obesity, and biodiversity, respectively .Given such mountains of papers, scientists cannot be expected to examine in detail every ...
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.
Abstract. Scientific review articles are comprehensive, focused reviews of the scientific literature written by subject matter experts. The task of writing a scientific review article can seem overwhelming; however, it can be managed by using an organized approach and devoting sufficient time to the process.
The best proposals are timely and clearly explain why readers should pay attention to the proposed topic. It is not enough for a review to be a summary of the latest growth in the literature: the ...
Writing a Literature Review. 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 ...
A good review article provides readers with an in-depth understanding of a field and highlights key gaps and challenges to address with future research. Writing a review article also helps to expand the writer's knowledge of their specialist area and to develop their analytical and communication skills, amongst other benefits. Thus, the ...
A literature review is a surveys scholarly articles, books and other sources relevant to a particular. issue, area of research, or theory, and by so doing, providing a description, summary, and ...
1. Outline and identify the purpose of a literature review. As a first step on how to write a literature review, you must know what the research question or topic is and what shape you want your literature review to take. Ensure you understand the research topic inside out, or else seek clarifications.
Analysis. The first step in writing a literature review is to analyse the original investigation research papers that you have gathered related to your topic. Analysis requires examining the papers methodically and in detail, so you can understand and interpret aspects of the study described in each research article.
3. Evaluate and select literature. 4. Analyze the literature. 5. Plan the structure of your literature review. 6. Write your literature review. Other resources to help you write a successful literature review.
The first step in writing a good literature review is to decide on the particular type of review to be written; hence, it is important to distinguish and understand the various types of review articles. ... Grech V. WASP (write a scientific paper): preparing an abstract. Early Human Development. 2018; 125:51-52. doi: 10.1016/j.earlhumdev.2018 ...
A literature review paper should flow logically from one topic to the next. As you write your paper, consider these tips: Write in a formal voice and with an impartial tone. Define critical terms and describe key theories. Use topic sentences to clearly indicate what each paragraph is about. Use transitions to make links between sections.
Literature reviews are valuable resources for the scientific community. With research accelerating at an unprecedented speed in recent years and more and more original papers being published, review articles have become increasingly important as a means to keep up-to-date with developments in a particular area of research.
Include this information when writing up the method for your review. 5 Look for previous reviews on the topic. Use them as a springboard for your own review, critiquing the earlier reviews, adding more recently published material, and pos-sibly exploring a different perspective. Exploit their refer-ences as another entry point into the literature.
Personal: To familiarize yourself with a new area of research, to get an overview of a topic, so you don't want to miss something important, etc. Required writing for a journal article, thesis or dissertation, grant application, etc. Literature reviews vary; there are many ways to write a literature review based on discipline, material type ...
Review of the literature may continue while organizing the material and writing begins. One way to organize material is to create an outline for the paper. ... Writing a scientific paper — a brief guide for new investigators. Vaccine 2017; 35 (5):722-8. 10.1016/j.vaccine.2016.11.091 [Google Scholar] 3. Sellers K, Leider JP, Harper E ...
Here you have a to-do list to help you write your review: A scientific literature review usually includes a title, abstract, index, introduction, corpus, bibliography, and appendices (if needed). Present the problem clearly. Mention the paper's methodology, research methods, analysis, instruments, etc. Present literature review examples that ...
Summaries and critiques are two ways to write a review of a scientific journal article. Both types of writing ask you first to read and understand an article from the primary literature about your topic. The summary involves briefly but accurately stating the key points of the article for a reader who has not read the original article.
Scientific review articles are comprehensive, focused reviews of the scientific literature written by subject matter experts. The task of writing a scientific review article can seem overwhelming; however, it can be managed by using an organized approach and devoting sufficient time to the process. …
To answer these questions, look at review articles to find out how reviewers view this piece of research. Look at research articles and databases like Web of Science to see how other people have used this work. What range of journals have cited this article? These questions were adapted from the following sources: Kuyper, B.J. (1991).
Thus, you probably already performed an extensive literature review to establish the current state of knowledge on the topic, and ensure the originality of your research when developing the protocol, and this can serve for your paper. ... Writing and publishing scientific papers. Gastroenterology, 142 (2012), pp. 197-200. View PDF View article ...
Abstract. This paper discusses the question about how to write a literature review paper (LRP). It stresses the primary importance of adding value, rather than only providing an overview, and it then discusses some of the reasons for (or not) actually writing an LRP, including issues relating to the nature and scope of the paper.
A systematic literature review is a method which sets out a series of steps to methodically organize the review. In this paper, we present a guide designed for researchers and in particular early-stage researchers in the computer-science field. The contribution of the article is the following: • Clearly defined strategies to follow for a ...
The fundamental rationale of writing a review article is to make a readable synthesis of the best literature sources on an important research inquiry or a topic. This simple definition of a review article contains the following key elements: The question (s) to be dealt with.