Groups of individuals with or without mental retardation, all of whom were currently on probation, were tested with measures of comprehension of Miranda rights and of suggestibility. As in previous work, participants with mental retardation were found to be less able to comprehend their Miranda rights. In addition, they were significantly more likely to respond to suggestive questioning and to change their answers. Significant correlations were found between measures of comprehension of Miranda rights and measures of suggestibility. Implications of these results were discussed.

Criminal defendants with mental retardation face special problems in the process of interrogation and confession, particularly with regard to the knowing, intelligent, and voluntary waiver of Miranda rights. Despite this, little attention has been paid to empirical measurement of this form of competency in mentally retarded adults. The present research uses scales originally developed by Grisso (1981) to measure competency to waive such rights in juveniles. Two samples of mentally retarded adults, one in a sheltered workshop setting and the other composed of current probationers, were tested. Both samples scored substantially lower on measures of Miranda comprehension than Grisso's samples of juveniles and adults. There were also differences between the samples that appear attributable to differential levels of criminal justice experience. It is concluded that the Grisso scales may be helpful in determining competency to waive Miranda rights in defendants with mental retardation. In addition, the present data raise strong concerns about the ability of many such defendants to make intelligent Miranda waivers. Policy recommendations are discussed.

The purpose of this study was to develop and validate an instrument for the assessment of competence to stand trial in criminal defendants with mental retardation. Three experiments were conducted on the instrument developed, Competence Assessment for Standing Trial for Defendants with Mental Retardation (CAST-MR). Experiment 1 consisted of three pilot testings with mentally retarded group home residents, Experiment 2 an expert appraisal process and readability analysis, and Experiment 3 a field testing with four groups of criminal defendants in five sites. Three forms of reliability-internal consistency, test-retest, and interrater-and three forms of validity-content, construct, and criterion-related-were investigated. The results of the reliability and validity analyses indicate that the CAST-MR may be a valid and reliable instrument for assessment of competence to stand trial in criminal defendants with mental retardation.

This study investigated the reliability and validity of the Competence Assessment for Standing Trial for Defendants with Mental Retardation (CAST-MR) with defendants with mental retardation referred for evaluation of competence to stand trial in the state of Ohio. The CAST-MR demonstrated strong internal consistency and interrater reliability. With respect to the instrument's validity, the group referred as competent had significantly higher total scores, significantly higher scores on each subsection, and significantly higher scores on seven individual test items. The results of discriminant function analyses further supported the CAST-MR's validity. These findings are discussed in relation to a previous CAST-MR validation study with a similar population.

The 2002 Supreme Court decision in Atkins v. Virginia prohibited the execution of defendants with mental retardation and required that professional standards be applied in the diagnosis of mental retardation in capital cases. Mental retardation diagnostic issues in Atkins cases can include: difficulties of retrospective data gathering, disagreement over the appropriate times of life at which mental retardation must be documented, difficulties in assessing adaptive behavior in the restricted environment of the prison, and the possibility of malingering. This article reviews the implications of Atkins for assessment and J.