Results of the longitudinal study of client outcomes indicated that substance abuse treatment programs for adolescents are relatively ineffective at reducing substance use and related problems among adolescents 12 months after treatment admission. Recommendations include the observation that case-mix adjustment models for evaluating substance abuse treatment effectiveness may not be enough because, for example, interpretation problems emerge when the proportion of cases providing follow-up data differs across programs. Overall, none of the programs examined was found to be consistently better than any other program across outcomes measurements. The authors point out that client risk profiles varied greatly between programs and as such, the poor client outcomes observed might reflect the risk profiles of the clients being served rather than the ineffectiveness of the treatment program. Another complicating factor to the interpretation of client outcomes was the high rate of institutionalization for clients at follow-up that were observed in the ATM samples. The findings raise questions about the ability to gain valid treatment performance outcome data from large-scale performance measurement efforts. The report suggests that a better approach to treatment evaluation might be to identify quality of care indicators for adolescent substance abuse treatment programs. In 1998, the Center for Substance Abuse Treatment, Substance Abuse and Mental Health Services Administration recognized the need for better information on the effectiveness of substance abuse treatment programs for adolescents and funded the ATM program, a grant program for independent longitudinal evaluations of the outcomes of youths admitted to treatment programs. One goal was to identify exemplary substance abuse programming, but the results failed to identify any particular program that was significantly better than any of the other programs. Several strategies are recommended to enhance the understanding of treatment effects among individual programs, types of programs, or geographic regions. Figures, tables, footnotes, appendixes, references