This is an archived version of the Handbook. For the current version, please go to training.cochrane.org/handbook/current.

Figure 10.4.a: Hypothetical funnel plots

Panel A: symmetrical plot in the absence of bias. Panel B: asymmetrical plot in the presence of reporting bias. Panel C: asymmetrical plot in the presence of bias because some smaller studies (open circles) are of lower methodological quality and therefore produce exaggerated intervention effect estimates.

 

Panel A

Panel B

Panel C