Random responding to the MMPI-2 F scale

Exact probabilities for a variety of F scale cutoffs are presented for detecting examinees who respond randomly to the MMPI-2 items.     

An evaluation of the usefulness of the MMPI-2 F(p) scale

The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) F(p) scale was developed by Arbisi and Ben-Porath (1995) by identification of 27 items endorsed by fewer than 20% of individuals in both normal and psychiatric samples. The F(p) scale was designed for applications in settings characterized by high base rates of serious psychopathology, such as psychiatric inpatient units, and is proposed as a useful scale in discriminating overreported protocols from those produced by patients with serious psychopathology. In this study we investigated the characteristics of this scale in a sample of 617 psychiatric inpatients who responded to the MMPI-2 under standard conditions, and 203 overreported protocols derived in research studies conducted with normal adult participants instructed to simulate various forms of serious psychopathology. Results of this study are consistent with prior reports of a relatively low frequency of item endorsement for F(p) scale items in psychiatric samples, and intercorrelations between the F(p) scale and the MMPI-2 basic clinical scales in clinical samples that are generally lower than those produced between either F or Fb and the basic clinical scales. However, this intercorrelational pattern between F(p) and the MMPI-2 basic scales was not as consistent for the overreported sample. Additionally, the F(p) scale appears to be effective in discriminating overreported from accurate MMPI-2 protocols, with some evidence that the optimal cutting scores for this and other MMPI-2 infrequency scales may differ as a function of gender. Finally, these findings do not show clear evidence of improved group prediction derived from the use of the F(p) scale in contrast to results obtainable through the use of the MMPI-2 F scale.     

MMPI-2 F scale as a predictor of acute versus chronic disorder classification

This study examined the relation between elevation of the infrequency (F) scale on the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) and the classification of psychological disorders as chronic or acute in an outpatient mental health setting. MMPI-2 and clinician rating data at time of intake were considered for 158 adult patients from an outpatient clinic. The results indicate that elevation on the F scale is associated with more chronic disorders even after the influence of other variables, such as age and comorbidity of other disorders, is statistically accounted for These results are discussed in terms of the utility and incremental validity of including the F scale as part of diagnostic screening.     

Stereopsis from reversible and irreversible patterns

Eight subjects reported stereoscopic depth as a function of the magnitude and direction of disparity carried by a reversible grid or an irreversible solid surface. The former alternated between a diamond seen against a grating or a uniform rectangular grid pattern with stereoscopic depth reported only when the diamond was perceived. Depth was attenuated for the grid compared to the solid surface patterns. Disparity can be defined by perceptually extracted forms with depth present only when those forms are bounded by visible contours.     

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.     

Refinement of the MMPI-2 F(p) scale is not necessary: a response to Gass and Luis

Gass and Luis (2001) reported that four MMPI-2 Lie scale items contained on the F(p) scale do not measure symptom exaggeration but measure defensiveness. They hold that elimination of the four Lie scale items improves the utility of the F(p) scale in the identification of exaggeration in VA samples. To directly address the assertion that removal of the L scale items from the F(p) scale enhances the predictive validity of F(p), data derived from a previously published study where 74 psychiatric inpatients were asked to retake the MMPI-2 and either feign psychopathology or respond in an honest manner were reanalyzed. The intact F(p) scale demonstrated a stronger correlation with group membership, increased incremental validity, and superior classification rates compared with the F(p) scale without the 4 Lie scale items. Consequently, the F(p) refinement recommended by Gass and Luis is unnecessary.     

Normative data for the F(p) scale of the MMPI-2: implications for clinical and forensic assessment of malingering

Data from several clinical samples and the Minnesota Multiphasic Personality Inventory--2 standardization group are presented to familiarize the reader with response patterns of different groups on a new validity scale designed to assist in the identification of exaggeration or fabrication of psychological disturbance. Sensitivity-specificity analyses are included along with suggestions for use of the F(p) Scale with other validity scales. Cautions about setting single cutoff scores are also discussed.