31/2021 Anna Bindler and Randi Hjalmarsson
Professional police forces are a fundamental part of criminal justice systems today. But how successful are police forces in reducing crime? This can be difficult for policymakers to measure because of the nature of the crime–policing relationship: policing affects crime levels and crime levels affect policing. We study this question by looking at the origins of this modern-day institution: the introduction of the London Metropolitan Police (the Met) in 1829. The Met was the first professional police force tasked with deterring crime. Our research uses historical records to evaluate the causal impact of this new institution on crime. Using newly digitised and geocoded crime and police data, we find evidence of a significant reduction in violent crimes.