The appropriateness of the MMPI-2 K correction

The extent to which the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) K scale serves as a suppressor variable that influences the validity of clinical scale scores was examined using 274 male and 425 female outpatients from a community mental health center and 105 male and 247 female clients from a university psychological clinic. Hierarchical regression analyses were performed with MMPI-2 K scale scores and clinical scale scores as predictors and therapist ratings as criteria. In most cases, the K scale did not act as a suppressor Optimal K weights were different from the traditional K corrections. In most instances, there were no significant differences between correlations of therapist ratings with K-corrected and uncorrected clinical scale scores. The results do not support the K scale as a suppressor variable in these settings, although additional research is needed in settings where higher levels of defensiveness are common.