This report from the Police Executive Research Forum (PERF) examines the impact of Compstat on police performance and accountability. Compstat is a "performance management system that is used to reduce crime and achieve other police department goals." The system has four core components and emphasizes information-sharing, responsibility and accountability, and improving effectiveness. The components are: 1) timely and accurate information or intelligence; 2) rapid deployment of resources; 3) effective tactics; and 4) relentless follow-up. The report has three major sections. The first section details what Compstat is and how it was developed and adopted, first by the New York City Police Department and subsequently by other law enforcement and non-law enforcement agencies. The second section of the report discusses what is known about Compstat in today's criminal justice system. The third section of the report discusses the future of Compstat and presents the views of agency officials on their plans for the use of Compstat. References and appendixes