Subjects for the comparative study consisted of 140 defendants admitted to the Forensic Unit at Mississippi State Hospital for court-ordered pretrial evaluation of competency between September 1984 and July 1986. A majority were charged with at least one violent offense. Subjects' scores on the CST and the GCCT were used to predict staff decisions about competency. Consistent with past research, the tests were highly correlated with one other and with the decisions of forensic examiners. Hit rates for the CST and the GCCT were 71.2 percent and 81.8 percent respectively. Patterns exhibited by the two tests suggest that they predict the competency criterion primarily by tapping an intellectual component of the competency construct. Tables and 20 references. (Author abstract modified)