These data collections collect comparable data over time to provide measures of how the country's jails, inmates, and staff have changed over time. The BJS corrections statistics program uses two distinct data collection methods: aggregate-level reporting by jail officials and self-reporting by inmates. These censuses and surveys provide data on issues facing jail administrators and a benchmark against which jurisdictions may compare their jail populations. Together the BJS censuses and surveys describe a jail population that is increasingly rapidly and experiencing significant changes. The number of jail inmates has more than tripled since 1970, when the first national jail statistics were collected. Flat budgets; steadily increasing data collection costs; and increasing demands for more accurate, timely, and operationally relevant data are leading to the use of computer-assisted personal interviewing and the redesign of the annual jail survey to reduce the amount of information collected to one page. Further changes and simplifications are also under consideration. Tables and illustrations