This study analyzed data from 1710 criminal defendants referred by federal courts throughout the United States. We examined 12 categories of criminal charges with respect to diagnosed psychopathology and opinions related to competence to stand trial (CST) and criminal responsibility (CR) at the time of the alleged offense. Overall, 18% of the present sample were found to be incompetent to stand trial, while 12% were found to be not criminally responsible or 'insane.' In this study, crimes were associated with rates of psychopathology and rates of opinions regarding CST and CR. The findings of this study suggest that individuals who are charged with different crimes have different mental states and psychopathology and are therefore found to have differential rates of competence and sanity.

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Mixed group validation (MGV) is offered as an alternative to criterion group validation (CGV) to estimate the true positive and false positive rates of tests and other diagnostic signs. CGV requires perfect confidence about each research participant's status with respect to the presence or absence of pathology. MGV determines diagnostic efficiencies based on group data; knowing an individual's status with respect to pathology is not required. MGV can use relatively weak indicators to validate better diagnostic signs, whereas CGV requires perfect diagnostic signs to avoid error in computing true positive and false positive rates. The process of MGV is explained, and a computer simulation demonstrates the soundness of the procedure. MGV of the Rey 15-Item Memory Test (Rey, 1958) for 723 pre-trial criminal defendants resulted in higher estimates of true positive rates and lower estimates of false positive rates as compared with prior research conducted with CGV. The author demonstrates how MGV addresses all the criticisms Rogers (1997b) outlined for differential prevalence designs in malingering detection research.

Common rates employed in classificatory testing are the true positive rate (TPR), false positive rate (FPR), positive predictive power (PPP), and negative predictive power (NPP). FPR and TPR are estimated from research samples representing populations to be distinguished by classificatory testing. PPP and NPP are used by clinicians to classify test takers into populations. PPP and NPP depend on the base rate (BR) of population members in the clinician's sample. The authors introduce the test validation summary (TVS) as a means to report within a single graph the FPR and TPR and the ranges of PPP and NPP across all potential sample BRs for any chosen cut score. The authors investigate how the TVS has other applications, including the estimation of local BR for the condition of interest and the estimation of standard errors for FPR and TPR when estimated across multiple independent validation studies of the classificatory test.

This article describes how a 2-alternative, forced-choice response technique was applied to a nonverbal test of cognition in order to generate measures of noncompliance and serve as a means to detect malingering. Three studies were conducted. Study 1 used a 2-alternative, forced-choice test format comprising 100 nonverbal test items of a hierarchy of difficulty presented in a random order. In a simulation study, a combination of decision rules regarding (a) performance curves slope; (b) a measure of response consistency ("consistency ratio"); and (c) the product of the slope and consistency ratio resulted in high discriminability among the test results of normal and cognitively impaired controls and simulating malingerers. A replication, Study 2, yielded similar findings. Study 3 demonstrated the robustness of these decision rules. Most subjects (73%) who simulated malingering after receiving accurate information on how to avoid detection were still classified as malingerers.Psychologists currently have no established objective methods of detecting malingering on the most commonly used instruments of cognitive, intellectual, or neuropsychological ability. The expanded use of such tests in both criminal and civil forensic evaluations increases the likelihood of impaired performances for secondary gain and necessitates the development of indicators of response validity (Bash & Alpert, 1980;Hiscock & Hiscock, 1989). This article describes how a test of cognitive ability was altered so that it could yield quantitative measures of noncompliance.Studies of clinical detection of malingering on cognitive tests are not encouraging. Patients are able to produce realistic findings of impairment on neuropsychological tests (Mensch & Woods, 1986), whereas clinicians are generally unable to detect malingered performance at better than chance levels (Faust,