Selecting an effective prevention program for a comprehensive intervention can be a daunting task. Not only must the program address the specific needs and assets of the defined population, but also there should be a level of confidence about its ability to produce positive outcomes regardless of differing settings and differing populations. The Comparison Matrix presented in this document is a table listing some 150 substance abuse and other problem behavior prevention programs that have been rated according to their effectiveness by five Federal agencies . The Comparison Matrix is intended for use by professionals in the field who wish to identify science-based prevention programs for implementation or for further research purposes. The Comparison Matrix consists of ratings or evaluations of prevention programs made by the Federal agencies that are most widely recognized as offering credible science-based assessments of prevention programs. The assessment criteria used by the various agencies is described in the appendix to indicate the differing approaches or perspectives of the rating agencies. (GCP)