Detecting random, partially random, and nonrandom Minnesota Multiphasic Personality Inventory-2 protocols.

Abstract

The ability of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2; J. N. Butcher et al., 2001) validity scales to detect random, partially random, and nonrandom MMPI-2 protocols was investigated. Investigations included the Variable Response Inconsistency scale (VRIN), F, several potentially useful new F and VRIN subscales, and Fb- F>or=30 and Fb>or=90. Protocols completed by 150 adults participating in custody evaluations at a juvenile court setting, screened for randomness with a matched-pair Millon Clinical Multiaxial Inventory-III (T. Millon, R. Davis, & C. Millon, 1997), were compared with 500 computer-generated all-random protocols and with three levels of partially random protocols. VRIN was the most effective scale in detecting uninterpretable random protocols; however, VRIN >or= 80 failed to identify 37% of them. Fb- F>or=30 and Fb>or=90 misidentified 41% of the 50%-65% random protocols as partially interpretable. Using the new scales, a decision algorithm was described that correctly classified 97%-100% of the protocols as interpretable, partially interpretable, or uninterpretable.