Micro Places – Carter et al. (2021)

Study Reference:

Carter, J. G., Mohler, G., Raje, R., Chowdhury, N., & Pandey, S. (2021). The Indianapolis harmspot policing experiment. Journal of Criminal Justice, 74, 101814.

Location in the Matrix and Methodological Rigor:

Micro places; General; Proactive; Very Rigorous; Mixed effects

What police practice or strategy was examined?

This study evaluated the effects of place-based policing in Indianapolis, Indiana from June to September 2019. Targeted areas were characterized by high levels of social harm, which was determined by calculating the monetary cost of crime and crime-related events (e.g., vehicle crashes). In areas driven by non-traffic related harms, officers were instructed to patrol by vehicle or foot and to hand out data-driven policing fliers. Officers in these areas were also encouraged to prioritize foot patrols in attempt to mitigate the negative effects of proactive policing on community trust and satisfaction. In areas driven by traffic-related harm, officers were instructed to park their vehicles in a highly visible position and issue a traffic citation if they observed any traffic violations. Officers in these areas were also provided with a handout detailing a range of local substance abuse services and administered the handout to any individual they suspected of having a substance abuse problem. Across all targeted areas, patrols were intended to last between 10-15 minutes.

How was the intervention evaluated?

A cluster randomized experiment was conducted to evaluate the intervention. A total of 78 patrol beats were block-randomized into the treatment or control group. In the treatment group, officer activities were directed at micro-places based on the monetary cost of social harms. In the control group, officer activities were directed to traditional violent crime hot spots and were limited to vehicle and foot patrols. Treatment and control groups were compared over a 100-day period using estimated social costs of crime/disorder events, calls for service, and arrests. In both groups, the top three harm/hot spots for each beat were selected continuously in three-hour time frames. Officers would direct their activities to one of the three areas for proactive policing.

What were the key findings?

In treatment areas, aggregated social harms and violent calls for service decreased. Though not statistically significant, in treatment areas property crime and drug overdoses also decreased. There were no reductions in crime in control areas. In treatment areas, there was an observed increase in traffic crashes. No diffusion or displacement effect was found within neighboring areas or during the three-hour window following the officers’ proactive policing activities. In treatment areas, there was an observed decrease within harmspots, though not statistically significant. The treatment areas had an increase in arrests of white and Black citizens and a decrease in arrests of Hispanic/Latino citizens. Finally, the harmspot policing condition reduced the monetary cost of social harms by $118,232, resulting in a cost-benefit of $38.6 per 10.4 minutes of officer proactivity.

What were the implications for law enforcement?

The authors suggest that the Indianapolis harmspot experiment shows the impacts of other ways in which police interventions at micro-places can be identified. It was noted that the operationalization of control hot spots may have led to results indicating no reductions in crime. The authors emphasize the potential benefits there may be in combining traditional hotspot policing strategies with a focus on social harm. The authors suggest the experimental conditions used in this study are likely adaptable by other law enforcement agencies.

Where can I find more information about this intervention, similar types of intervention, or related studies?