MMPI-2 Normative Data for the F-K Index: Implications for Clinical, Neuropsychological, and Forensic Practice

The F-K index has long been used as a validity indicator with the MMPI to help identify subjects who may be over- or underreporting psychological problems. The revision of the MMPI necessitates the collection of new norms and development of cutoff scores for the F-K index due to changes in the test itself as well as changes in the way subjects respond to items since the time of the development of the original test. Continuation of the use of old cutoff scores and clinical lore may lead to erroneous conclusions and decisions in the clinical and forensic arenas in which the index is used. MMPI-2 norms for the F-K index are provided for the standardization sample, and additional data are presented for samples of psychiatric patients, head injured patients, individuals seeking disability benefits, job applicants for police and priest positions, and substance abusers. Implications for use of the tables for interpretation of F-K scores are discussed.