Empirical Evaluation of the McMi—III Personality Disorder Scales
The MCMI–III personality disorder scales were empirically validated with a sample of 870 clinical patients and inmates. Prevalence rates of personality disorders were in general lower on the MCMI–III than clinical ratings, but trait prevalence was generally higher; thus a base rate of 75 on the MCMI–III could be a guideline in the screening of trait prevalence. However, the sensitivity of some MCMI–III scales was very low. Moreover, the correlations of most personality disorder scales of the MCMI–III were significant and positive with corresponding measures on clinical ratings and MMPI-2 personality disorder scales, but these were, in general, not significantly higher than some other correlations. As a consequence the discriminant validity seems to be questionable. The MCMI–III alone cannot be used as a diagnostic inventory, but the test could be useful as a screening device as a part of a multimethod approach that allows aggregation over measures in making diagnostic decisions.