Physics

Internal medicine

Funnel

Mathematics

Asymmetry

Meta-analysis

Particle physics

Statistics

Econometrics

Plot (graphics)

Forest plot

Publication bias

Funnel plot

Environmental science

Confidence interval

Medicine

Environmental engineering

Funnel plots, and tests for funnel plot asymmetry, have been widely used to examine bias in the results of meta-analyses. Funnel plot asymmetry should not be equated with publication bias, because it has a number of other possible causes. This article describes how to interpret funnel plot asymmetry, recommends appropriate tests, and explains the implications for choice of meta-analysis model

Recommendations for examining and interpreting funnel plot asymmetry in meta-analyses of randomised controlled trials