The results reported here were derived by updating a previously conducted meta-analysis of the effects of intervention on delinquency (Lipsey, 1992, 1995) with more recent studies. A subset of studies on serious offenders was selected from that meta-analysis, yielding 200 experimental or quasi-experimental studies of interventions for both noninstitutionalized and institutionalized serious offenders. The studies selected for the new database had the following characteristics:
Other studies included were those in which most or all of the juveniles
in the study had aggressive histories or those whose specific purpose
was to change aggressive juvenile behavior.