Profile of Embedded Validity Indicators in Criminal Defendants with Verified Valid Neuropsychological Test Performance

Abstract

Objective: Few studies have examined the use of embedded validity indicators (EVIs) in criminal-forensic practice settings, where judgements regarding performance validity can carry severe consequences for the individual and society. This study sought to examine how various EVIs perform in criminal defendant populations, and determine relationships between EVI scores and intrapersonal variables thought to influence performance validity.

Method: Performance on 16 empirically established EVI cutoffs were examined in a sample of 164 criminal defendants with valid performance who were referred for forensic neuropsychological evaluation. Subsequent analyses examined the relationship between EVI scores and intrapersonal variables in 83 of these defendants.

Results: Half of the EVIs (within the Wechsler Adult Intelligence Scale Digit Span Total, Conners' Continuous Performance Test Commissions, Wechsler Memory Scale Logical Memory I and II, Controlled Oral Word Association Test, Trail Making Test Part B, and Stroop Word and Color) performed as intended in this sample. The EVIs that did not perform as intended were significantly influenced by relevant intrapersonal variables, including below-average intellectual functioning and history of moderate-severe traumatic brain injury and neurodevelopmental disorder.

Conclusions: This study identifies multiple EVIs appropriate for use in criminal-forensic settings. However, based on these findings, practitioners may wish to be selective in choosing and interpreting EVIs for forensic evaluations of criminal court defendants.

Keywords: Effort testing; Embedded validity indicators; Forensic neuropsychology; Neuropsychology; Performance validity.