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.