Repeatable Battery for the Assessment of Neuropsychological Status: Effort Index Cutoff Scores for Psychometrically Defined Malingering Groups in a Military Sample.

OBJECTIVE: This research examined cutoff scores for the Effort Index (EI), an embedded measure of performance validity, for the Repeatable Battery for the Assessment of Neuropsychological Status. EI cutoffs were explored for an active-duty military sample composed mostly of patients with traumatic brain injury.

METHOD: Four psychometrically defined malingering groups including a definite malingering, probable to definite malingering, probable malingering, and a combined group were formed based on the number of validity tests failed.

RESULTS: Excellent specificities (0.97 or greater) were found for all cutoffs examined (EI ≥ 1 to EI ≥ 3). Excellent sensitivities (0.80 to 0.89) were also found for the definite malingering group. Sensitivities were 0.49 or below for the other groups. Positive and negative predictive values and likelihood ratios indicated that the cutoffs for EI were much stronger for ruling-in than ruling-out malingering. Analyses indicated the validity tests used to form the malingering groups were uncorrelated, which serves to enhance the validity of the formation of the malingering groups.

CONCLUSIONS: Cutoffs were similar to other research using samples composed predominantly of head-injured individuals.