What is Meta-Analysis?

Meta-analysis is a set of statistical techniques for combining data from independent studies to produce a single estimate of effect.

Meta-analysis is often used within healthcare, but is also applied in other disciplines including psychology and the social sciences.

Within healthcare, meta-analysis is often used to assess the clinical effectiveness of interventions; it does this by combining data from two or more studies (usually randomised controlled trials).

Meta-analysis of trials provides more precise estimates of treatment effect, by making use of all available data.

Meta-analysis is often part of the systematic review process, many systematic reviews include one or more meta-analyses.

The validity of any meta-analysis depends on the studies on which it is based.

Well-conducted meta-analyses aim for complete coverage of all relevant studies, look for the presence of heterogeneity among studies, and explore the robustness of the main findings using sensitivity analysis.