The detection of fake-bad and fake-good responding on the Millon Clinical Multiaxial Inventory III

The purpose of this study was to examine the effectiveness of the 3 Modifying Indices of the Millon Clinical Multiaxial Inventory III (MCMI-III) in the detection of fake-bad and fake-good responding. The sample consisted of 160 psychiatric outpatients. Paired t tests were performed to examine the effects of instructional set (faking vs. standard instructions). As hypothesized, instructional set produced significant differences on Scale X, Scale Y, and Scale Z in both fake-bad and fake-good analyses. Single-scale cutoff scores were as effective as multiple-scale cutoffs. The overall rates of successful classification indicated moderate effectiveness and utility of the MCMI-III Modifying Indices in the detection of dissimulated responding. When base rates were varied to more closely approximate a general clinical population, overall classification accuracy increased, but identification of faking (positive predictive power) gradually eroded with declining base-rate estimates. At lower base rates of faking, MCMI-III standard cutoff points yielded a high number of false positives.