Communities That Care (CtC) is an “operating system” developed by David Hawkins and Richard Catalano from the Social Development Research Group at the University of Washington, Seattle. The system empowers communities to use advances from prevention science to improve the well-being of children. It includes methods and toolkits and is supported by the CtC Prevention Strategies Guide, a list of 56 tested and effective prevention programs proven to reduce risk and increase protective factors. The CtC Youth Survey measures the incidence and prevalence of substance use, delinquency and related problem behaviors and the risk and protective factors that predict them.