The first study by Davis, Hoffman, and Quigley concluded that delinquents who successfully completed a PPC residential treatment program rated themselves as having a more positive self-concept upon discharge. The second study by Wasmund found that students from peer group agencies reported greater satisfaction with their social climates than their non-peer-group contemporaries, and staff/student perceptions were more congruent in the peer group agencies than in the non-peer-group agencies. The importance of testing the effectiveness of treatment models is emphasized. Further research is needed to determine whether PPC had discernibly different effects on males and females, different ethnic/racial groups, different age and grade levels, and different types of offenders. Further studies should also include more refined sampling procedures for selecting subjects and a method to determine the quality of what is actually delivered in treatment. The findings of the second study raise questions about the staff's expression in the daily life of the institution and their effects on the youngsters' progress in treatment and behavior after they leave.