An experiment involves studying two or more groups equivalent in all aspects except that one group receives a treatment -- arrest or counseling in domestic disturbance cases, for example -- and other groups do not. Policy experiments are becoming increasingly popular with criminal justice practitioners. The document discusses how field experiments influence public policy, how to choose the right policy question and critical issues in designing experiments, and it provides case studies in researcher-practitioner collaboration. It includes an article on identification, selective prosecution and enhanced treatment for serious, habitual juvenile offenders. The document also includes summaries of articles on alternatives to institutionalization; criminology; institutional corrections (adult); juvenile justice system; law enforcement; offenses; reference and statistics; staff resource development; technology/systems; and victim services.