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Public Thursday Seminar: Dr Barak Ariel, ‘Policing Hot Spots in London’

When Nov 21, 2019
from 05:30 PM to 07:30 PM
Where Seminar Room, Institute of Criminology
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Dr Barak Ariel

Jerry Lee Fellow in Experimental Criminology and Lecturer in Experimental Criminology


‘Policing Hot Spots in London’

Our understanding of causality and effect size in randomised field experiments is challenged by variations in levels of baseline treatment dosage in control groups across experiments testing similar treatments. The clearest design is to compare treated cases with no-treatment controls in a sample that lacks any prior treatment at baseline. We applied that strategy in a randomised test of hot spots police patrols on the previously never-patrolled, track-level platforms of the London Underground. The effect of 23,272 police arrivals at the treatment hot spots over 26 weeks was to reduce public calls for service by 21% on treated platforms relative to controls, yet interestingly primarily when police were absent (97 percent of the measured effect). The overall effect of the patrols was six times larger than the mean standardised effect size found in the leading systematic review on hot spots policing, with strong evidence of residual deterrence and no evidence of local displacement. In this Thursday Seminar, the results of this experiment, and how the study was executed, will be presented. Given these findings, and their implications for both research and policy, the Seminar will centre on future policing strategies, given the tide of 20,000 new police officers who are expected to enter police forces across England and Wales. As questions are now raised about how to best utilise these officers in the most effective way, the findings of this experiment have practical considerations for optimal deployment strategies.