Evaluating the latent structure of the MMPI-2 F(p) scale in a forensic sample: a taxometric analysis

P. A. Arbisi and Y. S. Ben-Porath (1995) originally proposed that the Infrequency Psychopathology scale, F(p), be used as the final step in an algorithm to determine the validity of a Minnesota Multiphasic Personality Inventory-2 (MMPI-2) protocol. The current study used taxometric procedures to determine the latent structure of F(p) among examinees with profiles that would necessitate the interpretation of F(p) when using Arbisi and Ben-Porath's proposed algorithm. Participants included a subsample of 289 consecutively referred pretrial forensic examinees adjudicated incompetent to stand trial with high Infrequency (F) scale scores, thereby providing a sample that would be expected to have a high base rate of persons with bona fide psychopathology and persons with incentive to overreport psychopathology. Using MAMBAC and MAXEIG, F(p) produced a taxonic latent structure within the subgroup of examinees who obtained raw scores on F of greater than 17. These results support Arbisi and Ben-Porath's original proposal to use F(p) to identify a distinct subgroup of overreported MMPI-2 protocols within forensic psychiatric examinees with high elevations on F. Implications and suggestions for future research are provided.