Understanding Systematic Reviews and 7 types of Systematic Reviews

Understanding Systematic Reviews and How to Write It

Understanding Systematic Reviews starts from preparing your mind towards making a transparent and unbiased analysis of information that is readily available. Systematic reviews are a sort of review that collects secondary data and analyzes it using repeatable analytical approaches. Systematic reviews are a sort of evidence synthesis that entails formulating broad or restricted research questions, as well as identifying and synthesizing data that is directly related to the systematic review issue. While some people associate ‘systematic review’ with ‘meta-analysis,’ there are a variety of ‘systematic’ reviews that do not include a meta-analysis.

Some systematic reviews assess research studies critically and synthesize qualitative and quantitative findings. Systematic reviews are frequently created to offer a comprehensive overview of existing evidence related to a research subject. Systematic reviews of randomized controlled trials, for example, are an important tool to inform evidence-based medicine, and reviewing existing research is generally faster and less expensive than starting a new one.

Key Features of a Systematic Review

In many different areas, such as evidence-based healthcare and evidence-based policy and practice, systematic reviews can be used to support decision-making. A systematic review can be created to provide a comprehensive overview of existing literature related to a research subject. A systematic review employs a method for research synthesis that is both rigorous and transparent, with the goal of identifying and, where possible, minimizing bias in the findings.

While many systematic reviews are based on an explicit quantitative meta-analysis of available data, qualitative reviews and other types of mixed-methods reviews follow guidelines for acquiring, analyzing, and reporting evidence. Statistical approaches (meta-analysis) are occasionally used to aggregate the results of eligible research in systematic reviews of quantitative data or mixed-method reviews. Depending on the methods used, scoring levels are occasionally used to grade the quality of the evidence, though the Cochrane Library discourages this practice. Multiple persons may be contacted to address any scoring disparities between how evidence is rated because evidence assessment can be subjective.

Types of Systematic Review

Mapping review/systematic map: A mapping review organizes and categorizes data from previous works of literature. The technique classifies literature by quantity and quality, as well as study design and other characteristics. The results of mapping reviews can be used to determine whether primary or secondary research is required.

Mixed studies review/mixed methods review: A meta-analysis is a statistical analysis that aggregates the findings of several quantitative investigations into a single report. Results from many studies are merged using statistical approaches to give evidence. Individual participant data are the two forms of data most commonly utilized in health research meta-analysis (such as odds ratios or relative risks).

Meta-analysis: A meta-analysis is a statistical method for combining the findings of several quantitative investigations. The results of many investigations are integrated using statistical methods to give evidence. Individual participant data and aggregate data are the two types of data commonly used for meta-analysis in health research (such as odds ratios or relative risks).

Qualitative systematic review/qualitative evidence synthesis: It involves the application of a hybrid methods to review, such as mixing quantitative and qualitative data.

Rapid review: This encompasses a search for and critical appraisal of existing studies using systematic review methodologies to examine what is already known about a policy or practice issue. Rapid reviews are still systematic reviews, but elements of them may be reduced or removed to speed up the process.

Systematic search and review: In systematic search and review, a thorough search strategy is combined with ‘critical review’ procedures. This is a frequent method of answering broad issues and synthesizing the best evidence. This method may or may not include a data source quality assessment.

Systematized review: encompasses elements of the systematic review process, but literature searching in systematized review is not as thorough as what can be seen in a systematic review. Furthermore; systematized review does do not always include data source quality checks.

Before you start writing your review

I know by now you might have become anxious to begin your review. Take my advice, don’t make the mistake of rushing into writing without making some key decisions that are most likely to make or mare your entire review. Firstly, you have to:

1. Decide on the databases you intend to seek your data from. Out there, they are so many databases, while some allow you to access journals and other scholarly materials for free, others demand membership registration and subscriptions. Additionally, some databases are discipline-specific in the sense that it houses journals and scholarly works from certain fields/research focus, while some accommodate journals from all research/academic fields. A good example of these types of databases is google scholar which is open to all research interests and PUBMED which accommodates majorly health and medicine journals.
2. What goal does the review seek to achieve? This can come in form of objectives for the review, what problems or solutions does the reviewer seek to highlight based on available works of literature in the study area. This does not only give the writer a direction but also enables you to formulate appropriate inclusion and exclusion criteria for the review.
3. Decide on what forms the inclusion and exclusion criteria. By inclusion criteria, it means the stipulated requirement that a journal needs to have for it to be included in the current study. Exclusion criteria on the other hand are the stipulated characteristics which if not present in a potential review journal, makes such a journal unfit or unsuitable to be included in the study being carried out. There are no generally stipulated inclusion and exclusion criteria for all studies, rather, inclusion and exclusion criteria are study-specific and are arrived at by the writer. It could be based on the methodology used, the language of publication, year of publication, number of the population used, the nature of the study (whether position papers, empirical research), study geographical scope or even sampling method among many others.
4. Decide on a literature search strategy: the literature search strategy to be used can be determined by the scope as well as the breadth of the objectives formulated by the reviewer
5. Decide on the appraisal tool to adopt in the review of journals to be included in the study. Ensure to use a methodological approach that is peculiar to the field of research you are into, which also allows you to evaluate all the essential aspects of the journals being reviewed. For instance, the CASP (Critical Appraisal Skill Program) have enjoyed widespread use in systematic review literature, mainly because it allows the reviewer to evaluate the various aspect of a journal, this includes, the data collection method, sampling techniques, data analysis method etc.
6. Lastly, you have to also consider how your findings will be presented. In most cases, a thematic review is often used. In thematic review, the reviewer presents the results of his/her findings based on predominant themes as relating to the issue being researched on the present in the works of literature reviewed.

When you are through with these above-named actions, you are sure ready to begin your review. We hope you have fun conducting your review.