The evaluations consisted of a physical examination, psychological testing, educational assessment, psychiatric examination, and social investigation. The findings indicate that juvenile delinquents are more often male than female, score lower on verbal than on performance intelligence tests, have lower achievement test scores than their grade level, score lower on standardized tests than the normal sample of children and adolescents, usually come from single parent families, and have different IQ score distributions among black, white, and Hispanic children. The principal finding is that 70 percent of the delinquents exhibit the developmental and disruptive behavior disorders of retardation, ADD-H, and ADD. The results indicate that medical, educational, and psychosocial interventions should offer testing, special education, parental training, family therapy, and cognitive skills development. The second hypothesis of the study, that delinquents without these conditions commit a higher number of offenses, is not confirmed. 25 references. (Author abstract modified)