Missing Data and Imputation in the Uniform Crime Reports and the Effects on National Estimates

The Uniform Crime Reporting (UCR) program has been a major source of data on crime since 1929. These data were long considered authoritative, but lately, questions have arisen about their accuracy. Maltz has documented the magnitude of missing data in the series and demonstrated their import for research on policy issues. Maltz's work focuses on agency-level estimates for specific months, but the UCR program was never meant to provide estimates for this unit or time period. So, although Maltz's work is important, it has not addressed the consequences of missing data for the principal purpose of the UCR program—providing annual national estimates of the level and change in crimes known to the police. This article complements Maltz's work by assessing the magnitude and distribution of missing data nationally and their effect on national-level and change estimates. It also examines the effects of the FBI's imputation practices on these estimates.