FOOT PATROL IN VIOLENT CRIME HOT SPOTS: THE LONGITUDINAL IMPACT OF DETERRENCE AND POSTTREATMENT EFFECTS OF DISPLACEMENT

This study revisited the Philadelphia Foot Patrol Experiment and explored the longitudinal deterrent effects of foot patrol in violent crime hot spots using Sherman's (1990) concepts of initial and residual deterrence decay as a theoretical framework. It also explored whether the displacement uncovered during the initial evaluation decayed after the experiment ended. Multilevel growth curve models revealed that beats staffed for 22 weeks had a decaying deterrent effect during the course of the experiment, whereas those staffed for 12 weeks did not. None of the beats had residual deterrence effects relative to the control areas. The displacement uncovered had decayed during the 3 months after the experiment, and it is theoretically plausible that previously displaced offenders returned to the original target areas causing inverse displacement. These results are discussed in the context of Durlauf and Nagin's (2011) recent proposal that prison sentences should be shortened, mandatory minimum statutes repealed, and the cost savings generated by these policy changes shifted into policing budgets to convey more effectively the certainty of detection. It is concluded that if Durlauf and Nagin's proposal is to succeed, then more holistic policing strategies would likely be necessary. Foot patrol as a specific policing tactic seems to fit nicely into a variety of policing paradigms, and suggestions for incorporating them to move beyond strictly enforcement-based responses are presented.