Validity Generalization and Situational Specificity: A Second Look at the 75% Rule and Fisher's z Transformation; Rejoinder

The James, Demaree, and Muliak (1986) critique of validity generalization (VG) methods and conclusions is analyzed and found to be flawed and to have no implications for the actual use of VG findings in applied settings. First, James et al. ignored the majority of published evidence against the situational specificity hypothesis and assumed that the 75% rule in individual meta-analyses was the only method for testing this hypothesis. James et al. also failed to distinguish between hypothesis testing and parameter estimation, and their critique of the 75% rule is a power argument that does not add to previous statistical power studies. Their use of Fisher's z transformation of r also creates an unnecessary inflationary bias in estimates of true validity. In a rejoinder, James et al. propose that their recommendations remain intact. Also, the implication of low statistical power for interpreting the results of a VG analysis is considered, and the possible need for a new mathematical model for VG is reviewed.