How To Conduct A Systematic Literature Review?

How To Conduct A Systematic Literature Review
STEP 1: FRAMING THE QUESTION

Step 1: Framing questions for a review.
Step 2: Identifying relevant work.
Step 3: Assessing the quality of studies.
Step 4: Summarizing the evidence.
Step 5: Interpreting the findings.

What are the methods for systematic literature review?

Abstract – This paper presents a method to conduct a systematic literature review (SLR) and meta-analysis studies on environmental science. SLR is a process that allowed to collect relevant evidence on the given topic that fits the pre-specified eligibility criteria and to have an answer for the formulated research questions.

Meta-analysis needs the use of statistical methods that can be descriptive and/or inferential to summarizing data from several studies on the specific topic of interest. The techniques help to generate knowledge from multiple studies both in qualitative and quantitative ways. The usual method has four basic steps: search (define searching string and types of databases), appraisal (pre-defined literature inclusion and exclusion, and quality assessment criteria), synthesis (extract and categorized the data), and analysis (narrate the result and finally reach into conclusion) (SALSA).

However, this work added two steps which are research protocol (define the research scope) and reporting results (stating the procedure followed and communicating the result to the public) at the initial and last step, respectively. As a result, the new method has six basic steps which are abbreviated as PSALSAR.

• The PSALSAR method is an explicit, transferable and reproducible procedure to conduct systematic review work. • It helps to assess both quantitative and qualitative content analysis of the literature review. • The procedure listed here added two basic steps (protocol and reporting result) on a commonly known SALSA framework.

What makes a good systematic literature review?

Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. A good SR also includes a comprehensive and critical discussion of the results, including strengths and limitations, such as assessment of bias, heterogeneity, and used definitions and categorizations.

How many studies should be included in a systematic review?

What Is the Minimum Number of Studies to Include in a Systematic Review? – There is no minimum number of studies to include in a systematic review. The number of studies you include in a systematic review largely depends on your research topic, as well as the amount of supportive evidence available.

How long should a systematic literature review take?

How Long Does it Take? Systematic reviews are done with a team of reviewers and they take a while to complete – at least 9 to 12 months depending on the topic. If you don’t have the time for such a large undertaking, consider carrying out a literature review or rapid review.

How long should a systematic literature review be?

The results should be presented and and their interpretation and implications discussed. Systematic reviews should be no longer than 5500 words. Implementation Science strongly encourages that all datasets on which the conclusions of the paper rely should be available to readers.

Do you need a hypothesis for systematic review?

Systematic reviews and meta-analyses: do it yourself – Even those not strictly committed to conduct a systematic review may obtain further insights into this clinical research method by understanding the key steps involved in the design, conduct and interpretation of a systematic review, Typical algorithm for the design and conduct of a systematic review. Modified from Biondi-Zoccai et al. (5). The next steps are very important, and define the boundaries of the reviewing effort. Specifically, the reviewer should spell out the population of interest, the intervention or exposure to be appraised, the comparison(s) or comparator(s), and the outcome(s).

The acronym PICO is often used to remember this approach. As an example, we could be interested in conducting a systematic review focusing on a population (P) of diabetics with coronary artery disease undergoing coronary artery bypass grafting, with the intervention (I) of interest being the administration of bivaridudin as anticoagulant, the comparator (C) being unfractioned heparin, and the outcomes (O) defined as in-hospital rates of death, myocardial infarction, stroke, or major bleeding (including bleeding needing repeat surgery).

After such preliminary steps, the actual review begins with a thorough and extensive search, encompassing several databases (not only MEDLINE/PubMed) with the help of library personnel experienced in literature searches, preferably also including conference abstracts and bibliographies of pertinent articles and reviews.

When a list of potentially pertinent citations has been retrieved, these should be assessed and included/excluded based on criteria stemming directly from the PICO approach used to define the clinical question.
Study appraisal also includes a formal evaluation of study validity and risk of bias of primary studies, whereas data abstraction, generally performed by at least two independent reviewers with divergences resolved after consensus, provides the quantitative data which will eventually be pooled with meta-analysis,

Indeed, provided that studies are relatively homogeneous and consistent, meta-analytic methods are employed to combine effect estimates from single studies into a unique summary effect estimate, with corresponding p values and confidence intervals for the effect ( Figure 5 ) Typical forest plot generated by RevMan from a systematic review with meta-analytic pooling of dichotomous outcomes (df=degrees of freedom; E=expected cases; O=observed cases; OR=odds ratio). The solid oval highlights event counts in one of the groups under comparison, the solid box shows graphically individual and pooled point effect estimates with 95% confidence intervals, the arrowhead indicates the exact pooled point effect estimate with 95% confidence intervals (CI), the arrow shows the p value for effect, and the dashed oval highlights p value for statistical eterogeneity and measure of statistical inconsistency (I2).

What are the three stages of systematic literature review?

The stages of a systematic review may vary slightly depending on the discipline and study types to be included but generally follow a series of steps outlined as follows:

Clarifying the problem, defining the research question and its boundaries, and setting out criteria for studies to be included in the review. This information, along with a plan for carrying out the review, should be presented in a protocol, Identifying studies, including selecting appropriate sources and searching for studies. Screening and selecting the studies, collecting and presenting the data from the studies, and / or describing the methods and findings of the studies using a structured approach. Appraising the relevance and quality of each study, which may involve assessing the risk of bias. Analysing and synthesising the data from the studies in order to answer the research question, which may involve a meta-analysis. Assessing reporting biases. Presenting results. Interpreting results and presenting conclusions.

Training and support available from UCL Library Services primarily focuses on the ‘Searching for studies’ stage of the process, but may include other stages in some circumstances.

What is the basic structure for a systematic review?

This article is part of a Series How To Conduct A Systematic Literature Review This article is part of a Series Key takeaways:

A systematic review is a thorough and detailed review of existing literature on a particular topic, designed to address a specific question.Systematic reviews are especially important in evidence-based medicine.A good systematic review begins with a protocol that defines the study design, objectives, and expected outcomes; follows the PRISMA guidelines, and should be registered in a recognized protocol registry.This article covers the basics of how to approach a systematic review and how such a review is typically structured.

What is a systematic review? A systematic review is a highly rigorous review of existing literature that addresses a clearly formulated question. The review systematically searches, identifies, selects, appraises, and synthesizes research evidence relevant to the question using methodology that is explicit, reproducible, and leads to minimum bias.

Systematic reviews are regarded as the best source of research evidence. Systematic reviews are absolutely crucial in the field of evidence-based medicine, but are also highly valued in other fields. A systematic review is more exhaustive than a literature review as it includes both published and unpublished literature, often called grey literature.

Grey literature is a significant part of a systematic review and adds value to the review. This is because grey literature is often more current than published literature and is likely to have less publication bias. Grey literature includes unpublished studies, reports, dissertations, conference papers and abstracts, governmental research, and ongoing clinical trials.

Qualitative: In this type of systematic review, the results of relevant studies are summarized but not statistically combined. Quantitative: This type of systematic review uses statistical methods to combine the results of two or more studies. Meta-analysis: A meta-analysis uses statistical methods to integrate estimates of effect from relevant studies that are independent but similar and summarize them.

Writing a protocol Any good systematic review begins with a protocol. According to the National Institutes of Health (NIH), a protocol serves as a road-map for your review and specifies the objectives, methods, and outcomes of primary interest of the systematic review.

The purpose of having a protocol is to promote transparency of methods. A protocol defines the search terms, inclusion and exclusion criteria, data that will be analyzed, etc. The protocol needs to be submitted to the journal along with your manuscript. Most journals expect authors of systematic reviews to use the PRISMA statement or similar other guidelines to write their protocol.

The PRISMA Statement: Anybody writing a systematic literature review should be familiar with the PRISMA statement, The PRISMA Statement is a document that consists of a 27-item checklist and a flow diagram and aims to guide authors on how to develop a systematic review protocol and what to include when writing the review.

Databases to be searched and additional sources (particularly for grey literature) Keywords to be used in the search strategy Limits applied to the search. Screening process Data to be extracted Summary of data to be reported

Registering systematic review protocols: Once you have written your protocol, it is advisable to register it. Registering your protocol is a good way to announce that you are working on a review, so that others do not start working on it. The available protocol registries for systematic reviews are:

Campbell Collaboration : Specific to systematic reviews of social interventions Cochrane Collaboration : Specific to systematic reviews of health care interventions PROSPERO : An open registry for all systematic reviews

The registries also provide a searchable database of registered reviews. Before starting a systematic review, you should search these databases for any registered reviews on the topic of your choice. This will ensure that you are not duplicating efforts.

What is the best approach to conducting a systematic review? The essence of a systematic review lies in being systematic. A systematic review involves detailed scrutiny and analysis of a huge mass of literature. To ensure that your work is efficient and effective, you should follow a clear process : 1.

Develop a research question 2. Define inclusion and exclusion criteria 3. Locate studies 4. Select studies 5. Assess study quality 6. Extract data 7. Analyze and present results 8. Interpret results 9. Update the review as needed It is helpful to follow this process and make notes at each stage.

This will make it easier for you to write the review article. If you wish to gain complete understanding of systematic review, check out this course designed exclusively for researchers by Gareth Dyke who manages the Taylor & Francis journal Historical Biology as Editor-in-Chief: Introduction to Systematic Review,

How is a systematic review article structured? A systematic review article follows the same structure as that of an original research article. It typically includes a title, abstract, introduction, methods, results, discussion, and references. Title: The title should accurately reflect the topic under review.

Typically, the words “a systematic review” are a part of the title to make the nature of the study clear.
Abstract: A systematic review usually has a structured Abstract, with a short paragraph devoted to each of the following: background, methods, results, and conclusion.
Introduction : The Introduction summarizes the topic and explains why the systematic review was conducted.

There might have been gaps in the existing knowledge or a disagreement in the literature that necessitated a review. The introduction should also state the purpose and aims of the review. Methods: The Methods section is the most crucial part of a systematic review article.

Inclusion and exclusion criteria Identification of studies Study selection Data extraction Quality assessment Data analysis

Results: The Results section should also be explained logically. You can begin by describing the search results, and then move on to the study range and characteristics, study quality, and finally discuss the effect of the intervention on the outcome.

Discussion: The Discussion should summarize the main findings from the review and then move on to discuss the limitations of the study and the reliability of the results.
Finally, the strengths and weaknesses of the review should be discussed, and implications for current practice suggested.
References: The References section of a systematic review article usually contains an extensive number of references.

You have to be very careful and ensure that you do not miss out on a single one. You can consider using reference management software to help you tackle the references effectively. You might also be interested in reading the folloowing related articles:

Which is easier to publish – an original research article or a review article? A young researcher’s guide to writing a literature review 6 Article types that journals publish: A guide for early career researchers

If you have any doubts or questions, you can post them in the comments section below. Alternatively, you can also a question on our Q&A forum if you are facing a problem and need expert publication advice. How To Conduct A Systematic Literature Review Published on: Apr 29, 2015

What are the 4 methods of literature review?

Over the years, numerous types of literature reviews have emerged, but the four main types are traditional or narrative, systematic, meta-analysis and meta-synthesis.

How many authors are in a systematic review?

How To Conduct A Systematic Literature Review The methodology for systematic reviews is designed to be rigorous and isn’t suitable for individual researchers and those working to a tight timescale. To learn more about different review methodologies and understand which type of review will best to undertake for your topic, we recommend you read ths following article: Grant, M.J.

Is there sufficent literature on your topic to warrant a review? As systematic reviews synthesise existing evidence and provide synthesis of published studies, it is a requirement that there is sufficent literature available on a topic for a review to be successful. You can carry out a scoping search (background search to assess the amount of literature available) before deciding on the best type of review to address your research question. If you find there isn’t much literature available on your topic then you may decide to conduct a ‘systematic search and review’ which aims to combine the strengths of the more traditional critical review with a systematic search process.

Do you have the time to complete a systematic review? Systematic reviews of medical interventions are carried out over a long period of time ( mean: 67.3 weeks ) and good quality, rigorous systematic reviews require multiple authors and experts to support the different stages of the review process. Reviewers should search multiple bibliographic databases (at least three relevant databases) to ensure that they have been comprehensive in their approach, and utilise other searching methods such as hand-searching to ensure all trials, or relevant studies are identified. Hand-searching is a manual process whereby an author identifies relevant studies for the review by examining citation lists in journal issues or in grey literature, The search process can be time consuming, so if you are on a tight deadline a different type of review methodology is likely to more appropriate.

Do you have methods to reduce the risk of bias in place? Systematic reviews follow a study protocol which details the methods that will be used in the review. Protocols are essential to ensuring a rigorous approach and can help verify that previous systematic reviews have not already answered the research question.

Do you have support available to work on the review? Systematic reviews should not be carried out by one person as this may lead to increased bias in searching, screening and data selection. A second person should be available for screening and article selection and this will reduce the chance of any errors made. Well conducted systematic reviews are carried out by teams with expertise in the topic under review, with the support of information professionals (librarians or information specialists) advising on the search strategy, database selection and reporting methods. If you are a current student, our team of librarians can advise you on good practice for search strategy formation and provide advice on searching databases efficiently. They will not be able to check your search strategy, or help you generate keywords as your search strategy will be assessed as part of your academic work.

There are many other types of review that you can undertake and often these are defined by the amount of time you have and the amount of literature that is available. Scoping reviews are often used to clarify gaps in knowledge or assess the literature available on a given topic.

Sometimes, they can be used to determine if a systematic review is necessary. This article provides information to help you understand the differences between these review types: Munn, Z., Peters, M.D.J., Stern, C. et al. Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach.

BMC Med Res Methodol 18, 143 (2018). https://doi.org/10.1186/s12874-018-0611-x You may find our guide on scoping reviews helpful.