A randomized experimental study of sharing crime data with citizens: Do maps produce more fear? ELIZABETH R. GROFF*, BROOK KEARLEY, HEATHER FOGG, PENNY BEATTY and HEATHER COUTURE University of Maryland, College Park, Maryland, USA * corresponding author: E-mail: egroff@ilj.org JULIE WARTELL San Diego County District Attorney’s Office, San Diego, California, USA Abstract. The larger roles of the community in crime prevention and improvements in technology have increased policeYcitizen communication and the distribution of information from police departments to private citizens. Combined, these changes have led to the current movement among law enforcement agencies toward sharing both summary reports and maps of crime with community groups. Although the dissemination of crime information is intended to benefit community members, there is a lack of empirical evidence demonstrating the effects of crime mapping on citizen perceptions and fear of crime. This experiment compared three formats for disseminating crime data; two popular types of crime maps (i.e., graduated symbol and density) and the traditional tabular format of crime statistics. A randomized experimental design was used to measure residents’ fear of crime and their perception of the safety of different areas of Redlands, CA. Overall, residents who viewed either type of map reported less fear than those who viewed tabular statistics. Respondents who viewed graduated symbol maps consistently reported less fear than either density maps or tabular statistics. However, there were differences depending on the type of map. While graduated symbol maps were associated with the lowest levels of fear of robbery, theft or assault; density maps produced different reactions depending on the area of the city. Finally, the maps did not stigmatize high crime areas of Redlands. Where statistically significant differences existed, respondents who were given maps were more likely to recommend someone move into an area than those who were given tabular statistics. Key words: community policing, crime data, fear of crime, geographic information systems, GIS, information sharing Introduction Recent shifts in police practice emphasizing the role of the community in crime prevention and the widespread adoption of technology have been accompanied by increased policeYcitizen communication (Sherman 1986), and more routine distribution of crime pattern and trend information from police departments to the public (Buslik and Maltz 1998; Maltz et al. 1989; McEwen and Taxman 1995; Rich 2001; Weisburd and Lum 2001). These efforts have been supported by Journal of Experimental Criminology (2005) 1: 87–115 # Springer 2005