An Ecological Model of Place-based Deterrence

Abstract Purpose The central premise behind place-based policing is that an intervention narrowly targeted to a location is able to suppress crime for some period of time. The crime-free survival time in a place ends with prolonged exposure to police action, known as initial deterrence decay, or after police have left, known as residual deterrence decay. The purpose of the present work is to understand the origin and character of deterrence decay at an aggregate spatial scale. Methods Deviating from previous efforts that explain deterrence decay based on the psychology of offender decision-making, the present work borrows ideas from theoretical ecology to model place-based deterrence as a form of competition between police and offenders over space. Deterrence decay emerges as a byproduct of this competition. Results When measured on an aggregate spatial scale, the model suggests that the waiting time to the emergence of crime and disorder from the onset of place-based policing actions should be gamma-like in distribution. The waiting time from the end of a place-based police action should be exponentially distributed. Conclusion If the model is a reasonable approximation of reality, then attempts to schedule place-based maintenance visits to counteract deterrence decay may be of limited value.