The Gang Resistance Education And Training (G.R.E.A.T.) program is an evidence-based and effective gang and violence prevention program built around school-based, officer-instructed classroom curricula. The program is intended as an immunization against delinquency, youth violence, and gang membership for children in the years immediately before the prime ages for introduction into gangs and delinquent behavior. The program is offered in both 6-week elementary and 13-week middle school program formats.