What is meta-analysis?
Author: Robert Hodgson
Meta-analysis is a set of statistical techniques for combining data from independent studies to produce a single estimate of effect.
Meta-analysis is most often used within healthcare, but is also applied in other disciplines including psychology and the social sciences.
Within healthcare, meta-analysis is most 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.