meta-analysis

Syllable breakdown

Dictionary meaning

a statistical method that combines the quantitative results of multiple independent studies addressing the same research question to produce a single, more precise and statistically powerful estimate of an effect size than any individual study could provide; meta-analysis is typically paired with systematic review — which identifies and qualitatively synthesises the available evidence — to produce the quantitative pooled estimate that places the synthesised evidence on a common metric; the core statistical procedure involves weighting each study's estimate by a function of its sample size and variance — usually the inverse of its variance — before calculating a weighted average; key analytical steps include testing for statistical heterogeneity — inconsistency in results across studies — and assessing publication bias — the tendency for studies with positive results to be published while null results remain unpublished; meta-analyses underlie clinical guidelines, regulatory decisions, and health technology assessments

Examples

• The meta-analysis of 47 randomised trials confirmed that the intervention reduced mortality by 22 percent across diverse settings.
• Funnel plot asymmetry in the meta-analysis suggested publication bias, with small negative trials apparently absent from the literature.