Two program components emerged as important across all reviews: service learning and mentoring. Service learning was a particularly crucial program component for youth ages 15 to 18.
The vast majority of programs reviewed were school-based and included young people of all ages. Whether such programs can be successfully implemented in a more voluntary setting (e.g., during nonschool hours and in out-of-school settings) is not clear.
There is little overlap between the measures collected in most of the evaluations summarized in these reports and the framework for positive adolescent development outlined in Part I. In part this reflects the fact that these studies were not designed to assess the features in this framework. But it might also suggest a scarcity of well-validated measures of personal and social assets and features of positive developmental settings (see Chapter 8 for more discussion of this issue). In part it also likely reflects the disconnection between research and practice traditions and points to the need for more collaborative efforts involving the research, practice, and policy communities in both designing and evaluating community programs for youth.
Most evaluation studies show modest short-term effects; some show longer-term effects, but follow-up data are rare and, when collected, rarely cover a period of more than two years after the program end. In general, follow-up studies tend to show smaller effects over time.
Most of the evaluations conducted in school-based programs included in this review met high technical standards for assessing effectiveness for individual children. However, these programs focused more on preventing negative outcomes than on fostering positive development.
Evaluations of more voluntary community-based programs are still less rigorous than the evaluations of school-based prevention programs. Possible reasons for this discrepancy are discussed in Chapter 7.