By making better use of available scientific evidence regarding the relative efficacy of prescription drugs, some states believe they can save money on their pharmaceutical assistance programs while ensuring the quality of care provided to enrollees. The Drug Effectiveness Review Project, a multistate collaborative effort initiated by former Oregon state officials, is attempting to use evidence-based research to help states design their pharmaceutical programs. In Phase 1 of this two-phase project, investigators will examine how participating states incorporate evidence-based research into their drug purchasing strategies and measure the preliminary impact on costs and utilization. If the first phase is successful, in the second phase the project team will examine the impact of a full year of evidence-based purchasing on costs, drug utilization, and quality of care. Project findings will inform all states about the benefits and challenges of using evidence-based research to control the costs of their prescription drug benefits. http://www.nashp.org