A Problem Checklist for school children developed by Peterson (1961) has been factor analyzed and modified through study of responses by male delinquents (Quay, 1964). Factors representing ( 1 ) aggressive acting-out, (2 ) neuroticism, and ( 3 ) inadeq~lacy were identified. The present study was designed to assess the reliability of Quay's factors and to analyze the utility of the rating scale in differentiating between successes and failures among parolees from a state training school. Ss included 65 recidivists and 59 nonrecidivists rated by their parole agents. There were no differences between the groups with respect to age, IQ, and time of institutionalization. Using factor loadings from Quay (1964), 32 items clearly loaded on a single factor were scored and split-half reliability coefficients determined. The reliability of Factor 3 ( .26) was not sufficiently high to justify further analysis, but Factors 1 ( .92) and 2 (.81) seemed both reliable and independent (r lz = .21). N o difference becween groups was observed for Factor 2 (MR = 7.15, SD = 4.13; MN = 6.19, SD = 5.12), but Factor 1, aggressive acting-out, yielded a significant difference (MR = 10.34, SD = 5.89; M N = 5.12, SD = 4.69; p < .0001) . Despite the fact that recidivists were rated as being the more aggressive group, there was significant overlap in the distributions of the two groups on Factor 1, and the correlation ( r b ) between recidivism and Factor 1 was only .55. At present the reliability of Quay's inadequacy factor remains to be demonstrated. Factors 1 and 2 appear to be highly reliable measures, applicable to adolescents as well as younger children. While it appears that recidivists as a group are more aggressive but nor more neurotic than successful parolees, overlap between groups is too great to allow valid prediction of parole adjustment for individuals on the basis of rated aggressiveness.