Flannery, et al. (2003) implemented the PeaceBuilders curriculum, which
focuses on reducing aggressive behavior and increasing social competence with
students grades K-5. They found increases in prosocial behavior and decreases in
teacher-reported aggressive behavior, with greater impact for those who were
initially lower in skills at the beginning of the study. The Warning Signs
curriculum did not show significant differences in experimental vs. control groups
in educating urban high school students about potential violence in themselves and
others (Schaefer-Schiumo & Ginsberg, 2003).