Figure 10.4.b: Contour-enhanced funnel plots

Panel A: there is a suggestion of missing studies on the right-hand-side of the plot, broadly in the area of non-significance (i.e. the white area where P > 0.1) for which publication bias is a plausible explanation. Panel B: there is a suggestion of missing studies on the bottom left-hand-side of the plot. Since the majority of this area contains regions of high statistical significance (i.e. indicated by darker shading), this reduces the plausibility that publication bias is the underlying cause of this funnel asymmetry.

 

Panel A

Panel B