PERC's mission is to use evaluation science to promote more effective and cost-effective care for veterans with substance use disorders. For the past 12 years we have substantially contributed to the development of an integrated body of knowledge about substance use disorders and their treatment that has helped the VA plan and implement a coordinated system of substance abuse care. To facilitate the VA's strategic objectives, we have the following goals:

• Monitor the organization and delivery of substance abuse treatment services: PERC conducts nationwide assessments of substance abuse treatment programs, monitors access to care, continuity of care, and program implementation and examines patients' treatment utilization and cost.

• Improve the process and outcome of interventions for patients with substance use disorders:PERC conducts evaluations of substance abuse treatment programs that focus on treatment process, environment, and staffing as well as outcome. Our understanding of how these variables interact to predict successful outcomes results in concrete recommendations for program improvement.

• Enhance treatment for co-morbidities that commonly occur in patients with substance use disorders: PERC conducts outcome evaluations of alternative substance abuse treatment settings and modalities designed to treat substance abuse and related co-morbidities such as psychiatric disorders, chronic pain, Hepatitis C and HIV. We find out what treatments work for each sub-population, and how to match patients to the best treatment for their specific condition.

• Encompass self-care and peer support interventions. Because they are effective and may reduce the cost of formal care, PERC's evaluations encompass self-care and peer-support interventions.

• Inform VA and other federal policies regarding substance abuse treatment: PERC conducts policy-relevant program evaluation as well as policy evaluation per se (e.g. evaluations of clinical policy, program policy, national policy). A related activity is the evaluation of clinical practice guideline implementation efforts.