The Sixty-Year Trajectory of Homicide Clearance Rates: Toward a Better Understanding of the Great Decline

Abstract

In 1962, the FBI reported a national homicide clearance rate of 93%. That rate dropped 29 points by 1994. This Great Decline has been studied and accepted as a real phenomenon but remains mysterious, as does the period of relative stability that followed. The decline was shared across regions and all city sizes but differed greatly among categories defined by victim race and weapon type. Gun homicides with Black victims accounted for most of the decline. We review the evidence on several possible explanations for the national decline, including those pertaining to case mix, investigation resources, and citizen cooperation. Our preferred explanation includes an upward trend in the standard for arrest, with strong evidence that although clearance-by-arrest rates declined, the likelihood of conviction and prison sentence actually increased. That result has obvious implications for the history of policing practice and for the validity of the usual clearance rate as a police performance measure.