What are systematic reviews?

Abstract

Systematic reviews are a type of review that uses repeatable analytical methods to collect secondary data and analyse it. Systematic reviews are a type of evidence synthesis which formulate research questions that are broad or narrow in scope, and identify and synthesize data that directly relate to the systematic review question.[1] While some people might associate ‘systematic review’ with 'meta-analysis', there are multiple kinds of review which can be defined as ‘systematic’ which do not involve a meta-analysis. Some systematic reviews critically appraise research studies, and synthesize findings qualitatively or quantitatively.[2] Systematic reviews are often designed to provide an exhaustive summary of current evidence relevant to a research question. For example, systematic reviews of randomized controlled trials are an important way of informing evidence-based medicine,[3] and a review of existing studies is often quicker and cheaper than embarking on a new study. While systematic reviews are often applied in the biomedical or healthcare context, they can be used in other areas where an assessment of a precisely defined subject would be helpful.[4] Systematic reviews may examine clinical tests, public health interventions, environmental interventions,[5] social interventions, adverse effects, qualitative evidence syntheses, methodological reviews, policy reviews, and economic evaluations.[6][7] An understanding of systematic reviews and how to implement them in practice is highly recommended for pro-fessionals involved in the delivery of health care, public health and public policy.