The BCS has been envisaged as a multipurpose vehicle which yields valuable policing related information. While illuminating crime levels and trends as a central aim, its modular structure allows for coverage of experience of the criminal justice agencies. This chapter gives a synopsis of the use made of the BCS in assessing performance, and in particular its central role in the Policing Performance Assessment Framework. Some inherent limitations in measuring performance with the BCS survey data are highlighted; however, the overall capacity of the survey yields valuable policing-related information. The coverage of policing issues in the 1980s and 1990s made a significant contribution to research knowledge about the police; the survey combined social indicator functions with research functions. The BCS recently acquired an important third function: to support central government’s work in assessing and monitoring police performance. The survey has broadened in purpose from being a source of understanding and knowledge about crime and justice to being part of the machinery of governmental control over the criminal justice system. Tables, figures, notes, and references