Psychometric limitations of the RBANS effort index in forensic inpatient populations

Abstract

Although the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) is a widely studied and utilized screening measure with an Effort Index (EI), there is a minimal amount of data available regarding the utility of the EI for forensic inpatients. Specific concerns include the possibility that the published cutoffs would result in high false positive rates. The present study investigated this issue by comparing the validity of the RBANS EI with that of the Dot Counting Test (DCT) and Test of Memory Malingering (TOMM) in a forensic psychiatric setting (N = 117). Analyses indicated a positive association between RBANS EI categorizations (invalid or genuine responding) and the classifications made by the DCT and the TOMM. However, the false positive rate for the RBANS EI was found to be excessively high (17.95%), while the positive predictive value was below chance (44.74%). Additional psychometric properties for the RBANS EI in this population are reported in the article, including findings from a Receiver Operating Characteristic (ROC) analysis. Overall, the results suggest that caution is warranted, when utilizing the RBANS EI as a validity measure within a forensic inpatient psychiatric setting and more appropriate cutoffs are needed for this population.