Convergent, Discriminant, and Concurrent Validity of Nonmemory-Based Performance Validity Tests

To supplement memory-based Performance Validity Tests (PVTs) in identifying noncredible performance, we examined the validity of the two most commonly used nonmemory-based PVTs—Dot Counting Test (DCT) and Wechsler Adult Intelligence Scale–Fourth edition (WAIS-IV) Reliable Digit Span (RDS)—as well as two alternative WAIS-IV Digit Span (DS) subtest PVTs. Examinees completed DCT, WAIS-IV DS, and the following criterion PVTs: Test of Memory Malingering, Word Memory Test, and Word Choice Test. Validity groups were determined by passing 3 (valid; n = 69) or failing ⩾2 (noncredible; n = 30) criterion PVTs. DCT, RDS, RDS–Revised (RDS-R), and WAIS-IV DS Age-Corrected Scaled Score (ACSS) were significantly correlated (but uncorrelated with memory-based PVTs). Combining RDS, RDS-R, and ACSS with DCT improved classification accuracy (particularly for DCT/ACSS) for detecting noncredible performance among valid-unimpaired, but largely not valid-impaired examinees. Combining DCT with ACSS may uniquely assess and best supplement memory-based PVTs to identify noncredible neuropsychological test performance in cognitively unimpaired examinees.

Examining the Test of Memory Malingering Trial 1 and Word Memory Test Immediate Recognition as Screening Tools for Insufficient Effort

Assessing effort level during neuropsychological evaluations is critical to support the accuracy of cognitive test scores. Many instruments are designed to measure effort, yet they are not routinely administered in neuropsychological assessments. The Test of Memory Malingering (TOMM) and the Word Memory Test (WMT) are commonly administered symptom validity tests with sound psychometric properties. This study examines the use of the TOMM Trial 1 and the WMT Immediate Recognition (IR) trial scores as brief screening tools for insufficient effort through an archival analysis of a combined sample of mild head-injury litigants ( N = 105) who were assessed in forensic private practices. Results show that both demonstrate impressive diagnostic accuracy and calculations of positive and negative predictive power are presented for a range of base rates. These results support the utility of Trial 1 of the TOMM and the WMT IR trial as screening methods for the assessment of insufficient effort in neuropsychological assessments.

The Booklet Category Test and Malingering in Traumatic Brain Injury: Classification Accuracy in Known Groups

A known-groups design was used to determine the classification accuracy of 12 Booklet Category Test variables in the detection of malingered neurocognitive dysfunction (MND) in traumatic brain injury (TBI). Participants were 206 TBI and 60 general clinical patients seen for neuropsychological evaluation. Slick, Sherman, and Iverson's (1999) criteria were used to classify the TBI patients into non-malingering, suspect, and MND groups. Classification accuracy of the BCT depended on the specific variable and injury severity examined, with some scores detecting more than 40% of malingerers with false positive error rates of 10% or less. However, the BCT variables are often influenced by cognitive ability as well as malingering, so caution is indicated in applying the BCT to the diagnosis of malingering. Application of these data in clinical practice is discussed.