Detection of Random Responding in MMPI-2 Protocols

Abstract

The present report represents a replication and extension of the Berry et al. (1991) study examining the utility of the standard second edition of the Minnesota Multiphasic Personality Inventory (MMPI-2) validity indices for detecting random responding. Specifically, relative to Berry et al., this study employs methodological improvements and investigates recently proposed alternative indices for detecting random responding. Another improvement includes the use of Bayesian statistics, including positive predictive power, negative predictive power, and hit rates, to select various cutting scores across three base rates of random responding. Results suggested that all validity indices studied differed significantly between random and valid protocols, although certain indices provided for more optimal hit rates in terms of classification. It is concluded that the alternative index, Variable Response Inconsistency (VRIN) scale plus the Infrequency (F) scale minus the Infrequency Back (F_B ) scale (VRIN + |F - F_B |) provided for the highest hit rate across all examined base rates of random responding. However, VRIN also provided for highly accurate classification rates and has specific advantages including the scale's repeated validation in the literature, its ease of use, and empirical findings suggesting that the scale is insensitive to overreporting.