Results of the study suggest that an overall null effect of placement exists on future rates of rearrest or self-reported offending for serious juvenile offenders. In addition, it was found that for the group placed out of the community, it was apparent that little or no marginal benefit existed for longer lengths of stay. The research results showed a general lack of support for lengthy periods of placement and indirectly underscored the movement toward increased use of non-placement/community-based alternatives. The effect of sanctions on subsequent criminal activity is of central theoretical importance in criminology. However, a key question for juvenile justice policy is the degree to which serious juvenile offenders respond to sanctions and/or treatment administered by the juvenile court. The policy question germane to this debate was finding the level of confinement within the juvenile justice system that maximizes public safety. To address this question, this study utilized longitudinal data from the Pathways to Desistance Study consisting of a large sample of serious juvenile offenders. The goal of the analyses was to identify two related yet distinct treatment effects: (1) the effect of placement and (2) the marginal effect of length of stay in placement. Tables, figures, references, and appendix