The study evaluates real-time impacts of various anti-crime interventions in Colombia.
In Bogot', one of Latin America's largest cities, 59 per cent of residents report feeling insecure. Newly elected Mayor Enrique Penalosa has made reducing crime and violence one of the central aims of his term, which runs from January 2016 to December 2019. However, there is little evidence on how the city government and police can reduce crime and build legitimacy cost-effectively. The results of the current study are expected to help the city to redeploy police and resources.
The evaluation will answer the following questions:
- What is the relative effectiveness of coercive and non-coercive interventions to increasing order and state legitimacy?
- Are these interventions cost-effective?
- What are the positive and negative spillovers of these interventions into the rest of the city?
The study includes two interventions. The first is a hotspot policing intervention that consists of increasing the dosage of patrolling time from about 55 minutes per day per hotspot street segment to 90 minutes, divided in six entries of 15 minutes each. Police patrols will be given specific instructions on how to distribute entries during the day. The activities the police perform while patrolling will be standard (e.g. criminal record checks, door-to-door visits to the community, arrests, drug seizures). For hotspots in the control group, police will not receive any special instructions and will be free to patrol as they see fit.
The second intervention is informed by the broken windows theory which suggests that crime may reduce through maintenance interventions such as cleanup and garbage pickup. However this has not been tested rigorously on a large scale in any country. This intervention will consist of sending a municipal team to selected hotspots to clean up streets, to signal state presence and order. The municipal team will be charged with repairing street lights, cleaning graffiti, and collecting garbage every few weeks.
Theory of change
The first intervention, hotspot policing, increases police presence in hotspots through the reallocation of police presence from street segments with less crime to those with more. Potential criminals and the community will then become aware of the increased police presence in these streets. The increased time police patrols spend in these segments increases the likeliness of apprehension and punishment. Because potential criminals are more likely to get caught, the expected cost of engaging in criminal activities in these areas rises. For some individuals, these higher costs will now outweigh the benefits of committing the crime so they will no longer commit the crime, leading to a decrease in crime. The second intervention aims to reduce street disorder and create an environment of lawfulness. Potential criminals will become aware of the improved physical environment and believe that police presence and other enforcement efforts are stronger at this location. Therefore, the subjective perception of apprehension and punishment will rise, increasing the cost of engaging in criminal activity and thus decreasing crime.
The study uses a randomised controlled trial design where street segments are randomly assigned to receive the intervention or not. To identify the experimental sample for the intervention, past crime data and verifications with police stations were used to identify 1,919 highest crime street segments. In addition to the experimental evaluation sample, data were also collected on a random sample of 550 no-hotspot streets. A street lighting and citizens survey will be conducted as well. As part of a bigger project, the current evaluation is aimed at estimating both the direct and indirect (spillover) effects of a largescale hotspot policing intervention and a largescale municipal services intervention.
The authors found a decrease in the number of reported crimes of about 12.6 per cent in streets targeted with intensive policing, and 10.2 per cent in streets targeted with municipal services. These differences, however, were statistically insignificant. On its own, intensive policing and municipal services did not lead to increases in security in hotspots.
The study did find that intensification of both forms of state presence simultaneously had large and statistically significant impacts on security. The results suggest there was a decrease of about 45.6 per cent in the number of reported crimes in streets targeted with both intensive policing and municipal services simultaneously. The combined effects of both interventions were largest on the highest crime hotspots.
An assessment of the displacement effects of the interventions revealed that the total crime deterred in targeted hotspots was modest and the results suggest that crime may have slightly increased in each of the (more than) 77,000 streets located within 250 meters of treated hotspot segments. When these displacement effects were added together, the study could not rule out the possibility that all directly deterred crimes were displaced to other neighbouring streets.
Implications for policy and practice
The authors conclude that intensive policing and municipal services alone do not lead to large or statistically significant increases in security around crime hotspots. However, the intensification of both forms of state presence simultaneously led to large positive impacts in security. Policymakers must make these place-based security interventions more effective on directly treated streets, for example, through more intensive state presence or less predictable policing. There is also a need to reduce the chances of adverse spillovers through various mechanisms, such as increasing general police presence, targeting crime clusters rather than individual segments, or combining place-based interventions with ones that target high-risk people and behaviours.
- Vigilancia redujo un 20 % el delito en puntos de m's criminalidad, El Tiempo, January 2017
- Intervenci'n en 'puntos calientes' redujo criminalidad, El Tiempo, January 2017
- En Bogot' fueron identificados 2.000 puntos cr'ticos en materia de criminalidad, RCN Radhio, January 2017
- Alcald'a deber' reforzar la presencia de uniformados y aumentar patrullajes: Santiago Tob'n, Caracol Radio, January 2017
- En Bogot' se redujo la inseguridad en un 20%
- Goverment press release