Counting cops: estimating the number of police departments and police officers in the USA

Recent federal legislation and numerous public policy debates have relied heavily on estimates of the number of police agencies and police officers in the USA. Historically, these estimates have been problematic, varying tremendously over time, across different sources, and using different methodologies. Currently, the two main sources of agency‐level data for estimating these numbers are the FBI’s Uniform Crime Reports and the Census Bureau’s Law Enforcement Directory Survey. While there is a great deal of overlap between these two databases, each contains thousands of departments not listed in the other. Also, among those departments listed in one or more of these databases, there is tremendous variation in the number of police officers recorded. While some of the disparity can be explained by banal differences in counting and record‐keeping methods, much is rooted in differing definitions of what constitutes a “police officer” and a “police agency”. In this study, we closely examine both databases in an effort to account for the differences between them. In addition, we introduce a new data source derived from the records of the Justice Department’s Office of Community Oriented Policing Services (COPS). Based on a thorough exploration of all three databases, we discuss the impact of their differences on criminal justice policy and police research. We first develop our own estimate of the number of police departments and police officers in the USA that differs substantially from other current estimates. We then estimate the number of police officers that the COPS office and future evaluators should use as the baseline for measuring the Clinton Administration’s success at adding 100,000 officers to the streets of America. Finally, we offer a modest set of recommendations for achieving greater uniformity across separate police agency databases.