The Fake Bad Scale and MMPI-2 F-Family in Detection of Implausible Psychological Trauma Claims

Abstract

We tested the validity of the Lees-Haley Fake Bad Scale (FBS) and the family of MMPI-2 F scales (F-family; F, F(p), and F-K scales) in predicting improbable psychological trauma claims in an applied setting. Litigants reporting implausible symptoms long after minor scares and nonlitigants clinically referred following severe stressors completed the MMPI-2. Both groups were naturally matched on social class. The FBS demonstrated sensitivity, specificity, and positive predictive power in the detection of atypical problems but the F-family showed poor utility. FBS cutting scores derived from logistic regression were applied to a third group made up of litigants with histories of undeniably severe traumas. A substantial number of this third group scored above cutoffs for exaggeration, but this finding is ambiguous. Reasons for the F-family's insensitivity to real-world exaggeration may include using student simulators for validation and content reflective of psychotic simulation. The superiority of the FBS in applied forensic settings could derive from its development in actual litigants and content reflective of nonpsychotic exaggerations. The FBS appears acceptable for use in applied forensic settings where persons seek compensation for nonpsychotic syndromes.

This study was unfunded and none of the authors have any financial interest in the FBS or the MMPI-2.

Notes

A priori cut score was set to equate specificity at 88% for males and females. Prevalence of improbable PTS is 48% in the female group, 63% in the male group, and 54% for combined sample. SENS = sensitivity; SPEC = specificity, PPP = positive predictive power, NPP = negative predictive power; Overall = overall hit rate; Incre. = incremental improvement over base rate guessing.

Twenty-one males and eleven females in the Lit-Maj group. The underlining refers to cutoff scores. Cum. Percent = cumulative percent.