Proposing a more conservative Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Effort Index cutoff score for forensic inpatient populations.

The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Effort Index (EI) may be unreliable at its standard recommended cutoff score when used with forensic psychiatric inpatient populations given high rates of genuine cognitive impairment. The present study sought to (a) examine the rate of invalid performance on the RBANS EI using the standard cutoff among incompetent to stand trial (IST) inpatients and (b) investigate the psychometric properties of the RBANS EI at various cutoff scores. This study was conducted using archival assessment data collected at a large forensic psychiatric hospital. Across the entire sample (N = 238, 79% male, M_age = 45 years, 24% primary Spanish-speaking), 79% were diagnosed with a schizophrenia spectrum disorder. Experiment 1 of the study (n = 165) contained IST patients who were classified as having a valid presentation. Experiment 2 contained a valid (n = 46) and invalid (n = 27) presentation group comprised of postadjudication and IST inpatients, respectively. In Experiment 1, over one third (36.4%) of the valid presentation sample scored above the standard recommended EI cutoff. In Experiment 2, applying the standard recommended cutoff score of > 3 was associated with a false positive rate of over 20%. Obtaining < 10% false positive errors was achieved at a cutoff score of > 5. At this cutoff score, the estimated local base rate of invalid responding among IST patients was 28%. Clinical and forensic implications and recommendations for adopting this more conservative RBANS EI cutoff score are discussed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).