Diagnostic validity statistics and the MCMI-III

This article (a) describes and illustrates the nonredundant and clinically important information that may be obtained from 5 diagnostic validity statistics (DVSs): incremental validities of positive and negative test diagnoses, Cohen's kappas, Cohen's effect sizes, and areas under receiver operating characteristic (ROC) curves and (b) determines values of these DVSs for 24 Millon Multiaxial Clinical Inventory III scales from results reported in 1994 and 1997 validity studies. The DVSs for the 1997 study (T. Millen, R. Davis, & C. Millon, 1997) were often more than 3 times larger than corresponding DVSs for the 1994 study (T. Millon, 1994). The author suggests these large differences could reflect not only effects of factors that caused underestimation of validities by DVSs of the 1994 study, but also effects of factors that may have caused overestimation of validities by DVSs of the 1997 study.