The program seeks to dissuade youths from delinquent behavior by teaching them skills, values, and attitudes which permit personal growth and by developing in them a sense of social responsibility. Instead of measuring effectiveness on the basis of recidivism, as most such evaluative literature does, the present study seeks to judge the effectiveness of the program by assessing psychological changes in the subjects during treatment. The study sample consists of 116 boys admitted to Boscoville from January 1974 to December 1975. About 56 of the subjects stayed at Boscoville for an extended period, while most of the others (60) left before completing 6 months of treatment. The 'treated' group is compared to the 'untreated' group using a battery of 30 psychosocial tests at various intervals. Results indicate that juveniles treated at Boscoville have made significant progress psychologically and behaviorally after a year of treatment. However, in the year after release from treatment, the boys tend to return to the level of their initial performance. During their treatment period, the most poorly developed youth make the most rapid developmental advances especially in maturation. But after release, this group relapses more rapidly than more advanced, stable subjects who take less rapid strides during treatment. Delinquent behavior decreases with treatment, but a number of subjects continue to commit offenses after release and have a tendency to abuse alcohol or drugs. Surprisingly, the ultimate social adaptation of the subjects is not related either to the initial level at the time of admission or to the progress made during treatment, but rather to the life style adopted by subjects after their treatment. Furthermore, social reintegration does not appear to be associated with particular familial or social circumstances during the first year after release. Thus, the treatment per se is only a contributory factor to the subjects' psychological and behavioral improvement. It is concluded that subjects who are relatively well developed psychologically at the beginning of treatment profit most from treatment. Furthermore, the most important changes in subject appear to occur in the first year of treatment, and little is gained by extending the program beyond 18 months. Finally, certain outside conditions strongly influence subjects' behavior after their treatment (e.g., choice of friends, frequent change of residence, and drug use), and it is unrealistic to believe that the subjects can be equipped during the treatment period to deal alone with all the outside temptations and challenges. The stay in a closed educational institution can only guarantee resocialization if combined with other modes of intervention in the subject's family, work, and studies to reinforce the treatment experience. Tables, notes, figures, and a bibliography are supplied.