The article in last month’s issue explored the place of systematic reviews in informing health care decision making. This article describes the core components of a high-quality systematic review of health care interventions. These components include an assessment of the risk of bias for individual studies, evaluation of the overall certainty of the body of evidence for the main outcomes, meta-analysis and the interpretation of the data. An understanding of these differing elements is the key to recognising the potential and important limitations of any systematic review.
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