Although the U.S. government spends billions of dollars annually on foreign assistance, there is no comprehensive tool to assist policymakers in assessing the state of a country's defense sector, to provide them with a systematic way of determining a country's capabilities to achieve various internal security goals, or to monitor the success of defense sector reform programs over time. In response, a RAND team developed the Defense Sector Assessment Rating Tool (DSART), which consists of six assessments to qualitatively and quantitatively determine the state of a country's defense sector, its institutions and processes, and its capacity to carry out operations for counterterrorism and counterinsurgency, counternarcotics, border and maritime security, counterpiracy, and postconflict stabilization. The DSART could be used to assess a country's current capabilities and then, over time, its progress. In addition, it could be used by countries other than the United States to assess their own defense sector capabilities or those of countries to which they are providing assistance. While the DSART is now ready for use, U.S. goals for defense sector reform may evolve, so the DSART is designed with a flexible architecture that can be adapted to a changing security environment.