General deterrent effects of police patrol in crime “hot spots”: A randomized, controlled trial

TLDR: In this paper, a one-year randomized trial in Minneapolis of increases in patrol dosage at 55 of 110 crime hot spots, monitored by 7,542 hours of systematic observations, showed that substantial increases in police patrol presence can indeed cause modest reductions in crime and impressive reductions in disorder within high crime locations.

Abstract: Many criminologists doubt that the dosage of uniformed police patrol causes any measurable difference in crime. This article reports a one-year randomized trial in Minneapolis of increases in patrol dosage at 55 of 110 crime “hot spots,” monitored by 7,542 hours of systematic observations. The experimental group received, on average, twice as much observed patrol presence, although the ratio displayed wide seasonal fluctuation. Reductions in total crime calls ranged from 6 percent to 13 percent. Observed disorder was only half as prevalent in experimental as in control hot spots. We conclude that substantial increases in police patrol presence can indeed cause modest reductions in crime and more impressive reductions in disorder within high crime locations.