Policing Crime and Disorder Hot Spots: A Randomized Controlled Trial*

Dealing with physical and social disorder to prevent serious crime has become a central strategy for policing. This study evaluates the effects of policing disorder, within a problem‐oriented policing framework, at crime and disorder hot spots in Lowell, Massachusetts. Thirty‐four hot spots were matched into 17 pairs, and one member of each pair was allocated to treatment conditions in a randomized block field experiment. The officers engaged “shallow” problem solving and implemented a strategy that more closely resembled a general policing disorder strategy rather than carefully designed problem‐oriented policing responses. Nevertheless, the impact evaluation revealed significant reductions in crime and disorder calls for service, and systematic observations of social and physical disorder at the treatment places relative to the control places uncovered no evidence of significant crime displacement. A mediation analysis of the isolated and exhaustive causal mechanisms that comprised the strategy revealed that the strongest crime‐prevention gains were generated by situational prevention strategies rather than by misdemeanor arrests or social service strategies.