An evaluative study was done of the Teen Outreach Program, a national, multi-site effort to reduce teenage pregnancy, school failure, and dropout. The study sought to identify the critical "active ingredients" of the program responsible for its success. The study was based on analyses of data collected at 114 different sites nationally, from September 1986 through June 1989, involving 1,950 student participants and 2,257 carefully matched comparison students. Outcomes for students were assessed in terms of the number of problem behaviors experienced by Teen Outreach and comparison students at a given site, both prior to entry into the program and after participation in it for 1 year. A cumulative analysis of the data produced a summary of what is currently known about the conditions under which Teen Outreach is most effective and the aspects of the program that account for its success. These findings indicated that important program components were volunteer service by participants and classroom climate. Program structure (during versus after school) did not affect outcome. Student characteristics of gender, race, ethnic status, and socioeconomic status do not affect outcomes. Teen Outreach was found to be most effective with middle school students. A fact sheet, one figure, and a brief program description are included. (JB)