The Puzzle of Clearance Rates, and What They Can Tell Us About Crime, Police Reform, and Criminal Justice

Abstract

Recent incidents of police violence have led to widespread reform efforts, from modest proposals to change police practices to dramatic attempts to slash funding or abolish the police entirely. But largely ignored in the debate is a simple question – how well is law enforcement currently performing its core functions? In particular, how good are the police at finding the perpetrator, arresting that person, and gathering enough evidence to start the matter through the criminal justice system? Answering this question requires close attention to the familiar, but under-studied, metric of clearance rates.

Clearance rates measure the percentage of reported crimes that are “solved” by the arrest of a suspect and the filing of criminal charges. But while these rates provide one valuable measure of police effectiveness, a closer look reveals both puzzles and qualifications, each of which raise important policy questions. Using original compilations of data, this article begins by looking at the puzzles. Clearance rates for violent and property crimes have been both quite low and amazingly steady for the last 40 years. These figures are counterintuitive, because during that same period, crime first rose and then decreased dramatically; law enforcement personnel numbers increased, and then flattened; and the legal enforcement landscape appears to have tilted in the direction of the police and prosecution. Each of these changes should have significantly affected the clearance rates, but even collectively, they did not.

The article then looks at possible explanations, and concludes that low and steady clearance rates are the product of relatively recent decisions about the role of police and the role of the justice system generally. Beginning in the late 1990s, when our model would predict that clearance rates would begin to increase, resources were increasingly diverted from solving traditional violent and property crimes. At the same time, a shift in law enforcement philosophy was gathering steam, one that prioritized crime prevention over crime clearance. This choice was a sensible one, as most would prefer to have fewer crimes committed rather than a higher percentage of crimes solved. But even these sensible choices have had important implications for crime victims, for criminal punishment schemes, and for the direction of police reform.

Keywords: clearance rates, policing, criminal procedure, arrests, police reform, victims' rights, justice reform