Classification accuracy rates of four TOMM validity indices when examined independently and jointly

Objective: This study investigated sensitivity and specificity rates of four Test of Memory Malingering (TOMM) indices (Trial 1, Trial 2, Retention, and Albany Consistency Index (ACI)) and examined how classification accuracy rates change when utilizing these indices in various combinations. Method: A sample of 202 neuropsychological outpatients was utilized. Patients were categorized as valid performers if they passed all criterion performance validity tests (PVTs) and were determined to be invalid performers if they failed two or more criterion PVTs. Classification accuracy statistics were obtained for individual TOMM indices as well as combinations of TOMM indices. Results: When using only Trial 1 as a validity indicator, the TOMM identified 57% of invalidly performing individuals. When all TOMM indices were examined, the ACI demonstrated the highest sensitivity value (63%) but it also demonstrated the lowest specificity value (91%). Allowing for failure of any of the four TOMM indices provided the best overall sensitivity value (67%) while maintaining adequate specificity (90%). Finally, it was determined that failure of three or more TOMM validity indices resulted in a specificity rate of 97% and failure of four of more TOMM validity indices resulted in a specificity rate of 98%. Conclusions: Classification accuracy of TOMM validity indices are discussed in relation to positive and negative predictive values. Results suggest that clinicians can examine all four TOMM validity indices concurrently, particularly in settings where high base rates of invalidity occur.