M is For Performance Validity: The IOP-M Provides a Cost-Effective Measure of the Credibility of Memory Deficits during Neuropsychological Evaluations

This study was designed to evaluate the classification accuracy of the Memory module for the Inventory of Problems (IOP-M) in a sample of real-world patients. Archival data were collected from a mixed clinical sample of 90 adults clinically referred for neuropsychological testing. The classification accuracy of the IOP-M was computed against psychometrically defined invalid performance. IOP-M <= 30 produced a good combination of sensitivity (.46-.75) and specificity (.86-.95). Lowering the cutoff to <= 29 improved specificity (.94-1.00) at the expense of sensitivity (.29-.63). The IOP-M correctly classified between 73% and 91% of the sample. Given its low cost, ease of administration/scoring in combination with robust classification accuracy, the IOP-M has the potential to expand the existing toolkit for the evaluation of performance validity during neuropsychological assessments.