Incremental Validity of MMPI-3 and NEO PI-3 Scores in Public Safety Candidate Pre-employment Psychological Evaluations

This study evaluated the incremental validity of the Minnesota Multiphasic Personality Inventory-3 (MMPI-3) and the NEO Personality Inventory-3 (NEO PI-3) scores in predicting California Commission on Peace Officer Standards and Training dimension (i.e., the POST-10) ratings in public safety (n = 754) pre-employment psychological evaluations (PPEs). Although research has supported the use of the MMPI and NEO PI instruments separately, no study has evaluated the use of these abnormal- and normal-range tests in conjunction, consistent with the POST Manual requirement of use of clinical and normal-range personality measures. The MMPI-3 and NEO PI-3 were completed during PPE. Problem ratings in the POST-10 dimensions were rated using information from the assessing psychologist's report. MMPI-3 and NEO PI-3 scores incremented one another in nearly every hierarchical ordinal logit regression model conducted to predict the ratings for five dimensions. Clinical implications and limitations, including potential criterion contamination especially for NEO PI-3 scores, are discussed.