Comparative validity of the MMPI and two short forms: psychiatric ratings.

Minnesota Multiphasic Personality Inventory (MMPI) scales were used to predict psychiatric ratings in two male and two female groups of adult state psychiatric hospital inpatients. The resulting regression coefficients were cross-validated on the other same-sex group using MMPI, MMPI-168, and Faschingbauer Abbreviated MMPI (FAM) scales as predictors. The validity coefficients obtained in this manner were generally small and similar across MMPI forms. There was a trend for MMPI-based predictions to be superior to those of the short forms as the validity coefficients grew larger. This finding suggested caution in the use of the MMPI-168 and FAM as substitutes for the full MMPI. A suggestive for blending realism and rigor in future research is offered.