Just enough police presence: Reducing crime and disorderly behavior by optimizing patrol time in crime hot spots

Using observational data collected as part of a one-year preventive patrol study in Minneapolis, this investigation employs survival models to test hypotheses about the effects of specific instances of police patrol presence at high-crime locations on the time until the next occurrence of criminal or disorderly behavior at these locations. The results show that patrol stops must reach a threshold dosage of about 10 minutes in order to generate significantly longer survival times without disorder — i.e., greater residual deterrence — than that generated by driving through a hot spot. The optimal length for patrol stops appears to be 11 to 15 minutes. After that point, continued police presence brings diminishing returns. The theoretical and policy implications of these results are discussed.