The national health objectives for the year 2000 call for 90% of the population to be served by a local health department (LHD) that is effectively addressing the core functions of public health. Achieving this objective requires approved definitions for effectiveness as well as a system for ascertainment. In 1990 when this objective was established, no baseline data were available, and no accepted methods of measuring health department effectiveness were in use. Our approach to the development of a surveillance system to measure the effectiveness of LHDs has been to translate the three core public health functions characterized by the Institute of Medicine and the 10 practices delineated by the Centers for Disease Control and Prevention (CDC) and the national public health practice organizations into practice performance measures that could be judged as met or not met at the level of a jurisdiction served by a LHD. As part of our effort to develop a surveillance system to measure local public health practice, performance measures that characterize the 10 public health practices and their related core functions were developed and field-tested with state local health liaison officials and local health departments over a two-year period. Obtaining input from these sources is essential to establishing their validity and is a critical aspect of building nationwide consensus for appropriate measures of effective local public health practice. The results of these efforts led to the establishment of a proposed surveillance instrument comprising 10 performance standards and 29 associated indicators. We describe two approaches to its use.