Tendency for smaller trials to report systematically larger effect sizes than larger trials.
Small-study effects describe the pattern where smaller trials within a meta-analysis report disproportionately larger treatment effects than larger, more precise trials. This can reflect publication bias, but may also stem from genuine clinical or methodological heterogeneity or lower trial quality, so the underlying cause is not always distinguishable from the pattern alone.
This guide was auto-drafted and is pending editorial review.