The development of surveillance systems faces challenges related to the current environment of limited public health resources and the proliferation of electronic data systems designed for other purposes. Further, compiling a picture of each firearm injury event requires accessing and linking data from multiple sources. One approach to the development of more efficient surveillance systems is to use health and other data being collected for other purposes. Useful data sources include police reports, crime reports, and newspaper clippings. Obtaining data for surveillance systems often requires the generation of data collection forms and active surveillance efforts such as data abstraction. Adequate resources need to be devoted to data analysis and to linking records from various data sources. The need for data validation procedures and standards is emphasized, cost and resource issues in surveillance system development are considered, and recommendations for the future development and use of surveillance systems are offered. 36 references