Results confirmed the importance of smaller program size and greater structure in ASPs. Specifically, students who attended larger programs experienced more delinquency and victimization. Other findings revealed that higher aggregate staff education and higher percentages of male staff were related to decreases in delinquency and victimization levels. The findings also implied that incorporating planned activities based on established instructional methods was most effective in preventing delinquency and victimization. ASP practitioners are encouraged to use these results to design smaller programs and hire more college graduates and males as staff members. Future research should further examine the relationship between unstructured socializing and victimization. Researchers began a formal outcome evaluation of 40 funded after-school programs in Maryland during September 2002. Programs were reviewed if they operated for more than 30 days during the school year, served at least 25 students in grades 4 through 12, had high attendance, and had lower drop-out rates than the remaining programs. The sample included 497 secondary school youth, 389 comprised the ASP treatment group and 108 comprised the comparison group. Parents or guardians of both groups completed pre- and posttest questionnaires measuring demographic characteristics. Student participants completed pre- and posttest questionnaires measuring self-reported delinquency, victimization, and substance use. Data on program characteristics were gathered from interviews with program directors and from attendance logs, provider information forms, and program observations. Data were analyzed using hierarchical linear modeling techniques. Tables, references, appendixes