A comparison of WMT, CARB, and TOMM failure rates in non-head injury disability claimants

Two-alternative forced-choice procedures have been the most widely employed for detecting incomplete effort and exaggeration of cognitive impairment. However, it cannot be assumed that different symptom validity tests (SVTs) are of equal sensitivity. In this study, 519 claimants referred for disability or personal injury related assessments were administered three SVTs, one based on digit recognition (Computerized Assessment of Response Bias, CARB), one using pictorial stimuli (Test of Memory Malingering, TOMM) and one employing verbal recognition memory (Word Memory Test, WMT). More than twice as many people failed the WMT than TOMM. CARB failure rates were intermediate between those on the other two tests. Thus, tests of recognition memory using digits, pictorial stimuli or verbal stimuli, all of which are objectively extremely easy tasks, resulted in widely different failure rates. This suggests that, while these tests may be highly specific, they vary substantially in their sensitivity to response bias.