Perhaps more than any other part of the criminal justice system, evidence based policy has taken hold in policing, and the police are looking to researchers to help them define what policies and practices they should adopt. A central area of evidence about what the police should do has come from studies of crime hot spots.
What is the evidence?
A series of studies show that crime is very concentrated in urban areas. In my own research I have found that in Seattle, New York, Sacramento and Tel Aviv between 4 and 5 percent of street segments, intersection to intersection, produce 50 percent of crime. In Seattle, we found that almost the exact same level of concentration existed year to year across sixteen years, irrespective of a declining crime trend in the period studied. And just 1 percent of the streets in Seattle that stayed chronically “hot” during this period producing almost 25 percent of crime.
Importantly, such crime hot spots are not concentrated in a single area, but are spread throughout the city. There are hot spots in so called good neighborhoods, and most streets have very little crime even in so called “bad” neighborhoods.
This law of crime concentrations led Lawrence Sherman and I to conduct a large randomized field study of hot spots policing based on Sherman’s finding that most crime calls in Minneapolis were concentrated at a relatively small number of street addresses. Randomly allocating police patrol to crime hot spots, we found that the police could significantly reduce crime on the streets that received hot spots patrol.
Our findings were in stark contrast to the prevailing assumption among scholars at the time that the police could not prevent crime. Subsequent research has confirmed our findings. Braga and colleagues identified 25 hot spots field tests, and found that 20 produced significant crime prevention benefits.
Crime does not get displaced
In turn, there is little evidence of crime being displaced to areas nearby. Indeed, not only does “crime not move around the corner,” there is strong evidence today that areas nearby are most likely to improve as a result of hot spots policing programs.
Based on this research I have argued that the police must refocus their paradigm of crime control from one that is centered on offenders to one that is centered on places. Policing places puts an emphasis on reducing opportunities for crime at places, not on waiting for crimes to occur and then arresting offenders. In this sense, place based policing is likely to produce at the same time a reduction of prison populations as well as an increase in the crime-prevention effectiveness of the police.
Chief Michael Davis, from Brooklyn Park, Minnesota, and I have recently added a new dimension to the promise of hot spots policing. Based on a recent study in which my colleagues and I found many social as well as opportunity based risk factors for chronic crime hot spots, Chief Davis and I have begun to argue for policing that increases collective efficacy and informal social controls at crime hot spots. The focus on crime hot spots provides an opportunity to “lower the scale” of social and health interventions making social interventions cost efficient.
As Latin American and Caribbean countries look to make their police actions more effective in the face of rising citizen concerns over violence, hot spots policing provides a good place to begin. Such policing should focus on increasing guardianship, solving problems, and reducing crime opportunities. But it should also consider social interventions at crime hot spots. Trying to increase collective efficacy and community social controls across a whole neighborhood may simply be impossible for police and other crime prevention agents. But focusing on just 1 percent of the city streets may make such interventions realistic for social interventions just as it does for law enforcement. Policing places is likely to be most effective if the police try to use not only strategies that increase surveillance and deterrence, but also ones that try to strengthen the micro communities that live in crime hot spots.
Prof. David Weisburd is a member of committee of experts advising the Inter-American Development Bank and a Distinguished Professor at George Mason University and Director of the Center for Evidence-Based Crime Policy. He also holds a joint appointment as the Walter E. Meyer Professor of Law and Criminal Justice at the Hebrew University Faculty of Law in Jerusalem. A version of this blog was originally published in the Police Executive Research Forum.