Institute of Criminology Public Seminars: 'Policing Hot Spots in London'

Speaker: Dr Barak Ariel, Lecturer in Experimental Criminology, University of Cambridge

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.

A drinks reception in the basement foyer will follow this seminar for attendees.

The IoC Public Seminar Series is open to all interested in attending, with no ticket required, but please notify Reception if you wish to attend: crimrece@hermes.cam.ac.uk.

If you wish to be added to the seminar mailing list, please contact: enquiries@cim.cam.ac.uk