Evidence-appraisal glossary
Contour-Enhanced Funnel Plot
A contour-enhanced funnel plot adds shaded regions marking levels of statistical significance to a standard funnel plot, helping distinguish publication bias from other reasons the plot might look asymmetric.
Also called: contour funnel plot.
In a plain funnel plot, asymmetry is ambiguous: it could mean missing studies or simply that smaller trials genuinely differ. By overlaying significance contours, this version shows whether the gaps fall in the non-significant zones, which is what you would expect if unremarkable studies went unpublished, or in significant zones, which points to other causes such as true small-study effects. It turns a vague visual impression into a more interpretable one, though it still calls for judgment rather than a mechanical verdict.
Read the full Reading the Evidence blog.
This is a plain-language methodology definition for reading research. It is general education, not medical advice.