The first evaluation, which was conducted from 1995 to 2001, found that the program reduced several risk factors associated with gang membership and delinquency; however, the evaluation found no differences in gang membership or involvement in delinquent behavior between youth who participated in G.R.E.A.T. and those who did not participate. Based on these findings, the curriculum was rewritten to address known risk factors for gang involvement. The new curriculum was piloted in 2001, with full-scale implementation in 2003. The latest national evaluation, which was conducted in 2006, shows that the program was implemented as intended and was well-received by schools. This latest evaluation also showed that the new curriculum resulted in several improved outcomes for participants. The evaluators found statistically significant differences between students in the G.R.E.A.T. classes and control students on 14 of 33 outcomes 1 year after participating students completed the program. Smaller but still significant effects on these outcomes continued after 4 years. The evaluators administered a pre-test and a 1-year follow-up questionnaire to gauge short-term program effects, and three additional annual surveys were conducted to gauge longer term effects of the program. The revisions to the curriculum and greater attention to teacher training have apparently resulted in modest improvements in program implementation and outcomes. The evaluation methodology and continuing challenges are discussed.