About Systematic Reviews

How Do You Critically Appraise a Systematic Review?

Systematic reviews have become highly important in the field of scientific research, especially since they help researchers and experts critically and impartially analyze complex literature for the most indisputable evidence. The systematic review process involves evaluating large volumes of published literature, including articles, books, etc.

However, you have to appraise your systematic review to ensure that the evidence collected is incontrovertible and relevant. Fortunately, there are several simple ways of appraising your systematic reviews. But why are systematic reviews good? And what is quality appraisal in a systematic review? This article will attempt to answer these and other related questions.

What Are Systematic Reviews?

Systematic reviews are structured and methodical assessments, of the available evidence to draw conclusions, which will guide important policy-making processes. A systematic review won’t be complete without an explicitly stated research question, a materials section, and a methods section. The research question of a systematic review is the specific clinical question that the evidence collected is supposed to answer, while materials are the relevant literature. The methods section comprises techniques used in data extraction, quality appraisal, and study data analysis. Types of data analysis commonly used are thematic, narrative, qualitative, and quantitative analysis. The type of included studies and the method used to synthesize results differ according to the type of review.

It’s important to note that all systematic reviews are not equal. Each review depends on the objectives of the study and the kind of literature to be evaluated. But you need to ensure that your systematic review includes all the pertinent trials, isn’t biased, and the synthesized results are factual and useful. To achieve this, you need to simplify your systematic reviews by incorporating the necessary tools. Fortunately, there are numerous software tools designed to help conduct systematic reviews of literature.

One of the advantages of systematic reviews is that they involve the appraisal of the quality of evidence. To assess the methodological quality of a systematic review, an assessment criterion is used. You can develop your assessment criterion or ‘borrow’ or modify an assessment criterion used by another author.

The appraisal of a systematic review helps dispel any doubts about the evidence you have collected, making the results of the review fully replicable. Systematic reviews also involve a conclusive analysis of all available information to offer reliable and factual results.

Appraising Systematic Reviews

In some instances, systematic reviews use meta-analyses, which involve the quantitative pooling of similar studies to generate the overall summary of evidence. The evidence from individual studies should be responsive to arithmetic analysis. You need to be certain that the review evidence you’ve collected is useful. Apart from appraising the quality of the systematic review, you can also appraise the quality of the included studies.  

  • When you are assessing the quality of your systematic reviews, you should ask yourself the following questions:
  • Does the systematic review clearly report and perform a complete and replicable literature search?
  • Does the systematic review frame a clearly focused question?
  • Does the review synthesize primary studies correctly?
  • Does the systematic review show how the results should be combined statistically?
  • Does the systematic review provide complete numbers and the right summary statistics?
  • Does the methods section of the systematic review clearly state the basis for inclusion or exclusion of primary Randomized Control Trials (RCTs)?
  • Does the systematic review report information like the size, relevant interventions, and outcomes from the primary RCTs?
  • Does the systematic review evaluate the procedural quality of primary studies?
  • Does the review discuss the reasons for variations or heterogeneity between individual RCTs and overall results?
  • Does the review report on the clinical relevance or benefits of the synthesized results?

Finally, take note that critical appraisal of systematic reviews uses a different methodology when compared to other appraisal tasks like the quality assessment of included studies. However, its principles are mostly based on the evidence collected and on the methodology of the review.

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