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Impact of Crime Maps on Public Perceptions

Impact of Crime Maps on Public Perceptions

Portland State University

Synopsis: Increasing public access to law enforcement data in an effort to enhance trust my produce counterproductive outcomes leaving agencies to carefully consider how information is presented.


Community Need

Law enforcement agencies are increasingly advised to, “establish a culture of transparency and accountability to build public trust and legitimacy” (Final Report of the President’s Task Force on 21st Century Policing). One of the things police agencies are doing to achieve this goal is to publish their crime statistics online. This includes aggregate crime counts and crime maps that allow people to visualize geographic patterns in local victimization. The assumption that increased access to this information will enhance public confidence in the police is largely untested. Similarly, crime statistics can be presented in different ways and we have little empirical knowledge about the impact of different strategies on public perceptions.


Primary Research Question(S)

Do crime maps (e.g., dot maps, density maps) produce less fear of crime, greater confidence in the police, and greater trust in one’s neighbors than aggregate crime statistics?

Research Design

Violent crime data for Portland were used to create dot and density maps for a police precinct in a fictitious city. Participants were then recruited from Portland State University students (N = 161) and a Community List-serve maintained by the Office of Neighborhood Involvement (112). Each participant was randomly assigned to one of the following six conditions:

  1. low crime – aggregate count map
  2. high crime – aggregate count map
  3. low crime – dot map
  4. high crime – dot map
  5. low crime – density map
  6. high crime – density map

People were asked to imagine that they live in the given police precinct. After reviewing their assigned crime map the participants answered questions about safety, confidence in the police, trust in their neighbors, etc.


Research Findings

As expected, people assigned to maps depicting a higher level of crime reported lower perceived safety, less confidence in the police, and less trust for their neighbors than people assigned to the lower crime conditions. Contrary to our hypothesis, people seeing dot maps felt significantly less safe, had less confidence in the police, and were less trusting of their neighbors than people who viewed the same data depicted in aggregate count maps and density maps.

Main Implications

Increasing public access to law enforcement data in an effort to enhance trust may produce counterproductive outcomes. Seeing hundreds, if not thousands, of crime dots on a map of one’s city may exacerbate fear of crime, result in decreased confidence in the police, and could negatively impact residents’ willingness to work together to address public safety issues. Law enforcement agencies are encouraged to carefully consider how they present information to the public and be attentive to possible harmful impacts. This is especially true with dot maps.


Bonn, K., Henning, K., Harmon, M., & Skinner, A. (2015, November). Putting Crime on the Map: Impact of Aggregate Crime Counts Versus Dot and Density Maps on Citizen Perceptions. American Society of Criminology, Washington, D.C.