Hot Spots Policing in a High Crime Environment: An Experimental Evaluation in Medellín

Abstract

Objectives: Test direct, spillover and aggregate effects of hot spots policing on crime in a high crime environment. Methods: We identified 967 hot spot street segments and randomly assigned 384 to a six-months increase in police patrols. To account for the complications resulting from a large experimental sample in a dense network of streets, we use randomization inference for hypothesis testing. We also use non-experimental streets to test for spillovers onto non-hot spots, and examine aggregate effects citywide. Results: Our results show an improvement in short term security perceptions and a reduction in car thefts, but no direct effects on other crimes or satisfaction with policing services. We see larger effects in the least secure places, especially for short term security perceptions, car thefts and assaults. We find no evidence of crime displacement but rather a decrease in car thefts in nearby hot spots and a decrease in assaults in nearby non-hot spots. We estimate that car thefts decreased citywide by about 11 percent. Conclusions: Our study highlights the importance of context when implementing hot spots policing. What seems to work in the U.S. or even in Bogotá is not as responsive in Medellín (and vice versa). Further research-especially outside the U.S.-is needed to understand the role of local crime patterns and police capacity on the effectiveness of hot spots policing. JEL codes: K42, O17, E26, J48, C93.

Policing Directions: A Systematic Review on the Effectiveness of Quantitative Police Presence

“…(1) measurable police presence. Suitable studies reported police presence in quantitative measures, e.g., time of police presence, number of visits, hours of officers per police beat, or length of patrol shifts (e.g., Bowers and Hirsch 1987, Kaplan et al 2000, McGarrell et al 2001, Zech et al 2005, Ratcliffe et al 2011, Taylor et al 2011, Novak et al 2016, Stephensen 2017, Ariel et al 2019, Collazos et al 2020. This excluded studies that either focused on police expenditures (McPheters and Stronge 1974), police personnel (Levine 1975, Levitt 2002, or tried to infer a level of police presence from law enforcement actions such as arrests rates (Weisburd et al 2016).…”

“…Police action does not just work best when focused on target areas but also when focused on certain types of crime. Police presence has particular strong crime reduction effects on motor vehicle theft (Di Tella and Schargrodsky 2004, Collazos et al 2020, Piza et al 2020, violent crimes (Ratcliffe et al 2011, Taylor et al 2011, Novak et al 2016, and property crime (Andresen and Lau 2014). Similarly, gun related crimes Rogan 1995, Rosenfeld et al 2014) and liquor inflictions (Fitterer et al 2017) experienced substantial reductions.…”

“…In spite of displaced crimes, the net reduction effect stood at 53 prevented violent crimes (Ratcliffe et al 2011). Many studies accounted for crime displacement or found no support of this side-effect (e.g., Esbensen and Taylor 1984, Rosenfeld et al 2014, Ariel et al 2016, Collazos et al 2020).…”

“…However, in many cases no change in the feeling of safety nor fear of crime was detected (Kelling et al 1974, Kelling et al 1981, Weisburd et al 2011. Collazos et al (2020) reported an increase in the perceived level of safety in crime hot spots for the six-month intervention period. After that, no differences in perception were examined between treatment and control area.…”

“…GPS-based technologies have been confirmed as the most precise option to track and measure police presence, as they can collect positional and temporal information at a high rate (Ariel et al 2016, Collazos et al 2020. Trackers can be used in body-worn officer radios (Hutt 2020) or installed in police vehicles as AVL (Automated Vehicle Locators) (Mitchell 2017).…”