Evidence-appraisal glossary
Egger's Test
Egger's test is a statistical check for funnel plot asymmetry, used to detect small-study effects such as publication bias in a meta-analysis. It quantifies whether smaller studies give systematically different results than larger ones.
Also called: Egger regression test, Egger's regression.
A symmetric funnel plot suggests that a study's size is unrelated to its result; asymmetry hints that small studies with unremarkable findings are missing. Egger's test formalizes this by regressing the effect estimate against its precision and testing whether the intercept departs from zero. A significant result is a warning, not a diagnosis, because asymmetry can arise from genuine differences between small and large trials or from chance when few studies are pooled, so it should never be read as proof that results were suppressed.
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This is a plain-language methodology definition for reading research. It is general education, not medical advice.