Crime Rates,Clearance Rates and Enforcement Effort: The Case of Houston,Texas*

Abstract . Two time series relationships with respect to police and criminal activities are analyzed. These relationships are: 1. That between police input and police output where the latter was measured by arrest and convictions rates and the former by expenditures and number of officers and, 2. The hypothetical one between the probability of arrest (the clearance ratio; i.e., the proportion of reported crimes for which arrests were made) and crime rates. Theoretically, an increase in expenditures for police effort would cause an increase in the clearance rate and a concomitant reduction in the crime rate. The results of this study showed little or no response in clearance and crime rates to small changes in police expenditures. However, there was evidence that large changes in police effort did produce some response in both clearance and crime rates. The implication of these findings was that the marginal product of police input was small.