An analysis of the differential power of the Fake Bad Scale of the MMPI-2

This study examined the ability of the Fake Bad Scale of the Minnesota Multiphasic Personality Inventory-2 to differentiate among individuals who have a traumatic brain injury, individuals with a somatoform disorder, and individuals who are malingering. Participants were chosen from a pool of 283 personal injury and workers compensation cases obtained from an established neuropsychological practice in a major Southwestern city. Each of these participants was involved in litigation and received a diagnosis that included traumatic brain injury, a somatoform disorder, or malingering. Complete neuropsychological and psychological test batteries were conducted on each participant, and the complete medical records for each participant were reviewed. Of the available cases 30 individuals with a diagnosis of malingering, 31 individuals with a diagnosis of a somatoform disorder, and 21 individuals with a traumatic brain injury were selected for analysis.;The first aspect of the Fake Bad Scale that was examined was its ability to differentiate among individuals with traumatic brain injury, a somatoform disorder, or who are malingering. These data were analyzed utilizing a one-way Analysis of Variance (ANOVA). The ANOVA indicated that the mean Fake Bad Scale scores for each group were significantly different; thus, a Bonferroni comparison was made. This comparison demonstrated that the Fake Bad Scale significantly differentiated between each possible pairwise comparison of the three groups of interest in terms of mean score. The sensitivity and specificity of the Fake Bad Scale were also examined and indicated that significantly different mean scores did not necessarily imply accuracy of classification given that the Fake Bad Scale correctly classified individuals with Somatoform Disorder less than 50 percent of the time.;Next, the Fake Bad Scale of the MMPI-2 was compared to other validity measures of the MMPI-2 by using a separate one-way ANOVA for each validity scale of interest These analyses indicated that the F Scale, the F-K Index, and the F(b) Scale each produced significantly different mean scores for the three groups of interest. Subsequent Bonferroni comparisons indicated that none of these scales significantly differentiated between malingerers and individuals with a traumatic brain injury. The sensitivity and specificity for each MMPI-2 validity scale were also considered, and resulted in the conclusion that the F(b) Scale provided the most consistent classification of each diagnostic group.;The final question that was considered was whether there were gender differences in the ability of the Fake Bad Scale to differentiate among the three groups of interest. These data were analyzed using Analysis of Variance (ANOVA). Gender differences on the Fake Bad Scale were not found.