A Rational Theory of Random Crackdowns∗

This paper develops an incentives-based theory of policing that can explain the phenomenon of random “crackdowns,” which are intermittant periods of especially high interdiction/surveillance. We show that, when police minimize the crime rate, random crackdowns can emerge as part of an optimal policing strategy. We consider several variations of the basic policing model that would apply in different monitoring situations, such as speeding or drug interdiction, or screening to deter terrorism. For a variety of police objective functions, random crackdowns can be part of the optimal monitoring strategy. We demonstrate support for several implications of the crackdown theory using traffic data gathered by the Police Department in Belgium, and we use the model to estimate the deterrence effect of additional resources spent on speeding interdiction. ∗We are grateful to Larry Samuelson for useful discussions. This paper was improved by comments received at the University of Pennsylvania IER crime conference, at the Northwestern NSF conference on profiling, and at seminars at UBC, Columbia, Duke, and Brown. We are also grateful to the Belgian police department for the data and for their assistance in interpreting the data. This project was supported by the National Science Foundation Grant SES-0422862. †Department of Economics, 3718 Locust Walk, Philadelphia, PA 19104. Emails: [email protected], [email protected], [email protected].