Another relevant question concerns the validity of the selective publishing scenario. It surely has some merit, since it explains the Proteus phenomenon that has occurred in some research areas [1], [22]. We argue, however, that in many research fields studies are most likely to be published when they report effects that are significantly different from zero rather than from the effect estimated in cumulative meta-analysis. The evidence for this type of publication bias is overwhelming. For instance, Fanelli [2], [3] observed a high percentage of ‘positive’ (significant) results in many sciences, particularly in social sciences, e.g. psychology (about 95%, [3], p. 898). This high percentage cannot be explained by studies’ statistical power since power generally is low and there is no evidence that it has grown over the years ([3], p. 899). The high percentage is indicative of publication bias, i.e., the bias introduced by tendencies to mostly submit and publish results that are statistically different from zero.
