The NCS program is a continuing survey of a probability sample of U.S. households to determine the frequency and nature of the criminal victimizations they have experienced. The NCS is designed to compile a more complete picture of crime than is possible by using only police statistics, which contain only reported criminal victimizations. Because of its large sample size and significant amount of information about individual victims and victimizations, the NCS is useful to researchers. Periodic questionnaire revisions and supplements have enhanced its utility over the years, and forthcoming changes will further enhance it. Some limitations of the NCS pertain to its failure to cover series victimizations, victimization contexts, and the process features of victimizations; measurement of assaultive crimes; use of panel features; geographical disaggregation; and timeliness.