A Second Validation Study of the Competence Assessment for Standing Trial for Defendants with Mental Retardation (CAST-MR)

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.