In cities where crime tends to be concentrated in a small number of places, police forces often adopt geography-based approaches to crime reduction. However, increasing policing in one area may simply displace crime to another area, leaving the overall level unchanged. Researchers are working in Bogotá, Colombia to assess whether concentrated policing or increased municipal clean-ups in high-crime areas can reduce—rather than simply displace—crime.
In most cities around the world, crime is concentrated in a small number of places, which police often call crime “hot spots.” Hot spot policing, in which police spend increased time in higher-crime areas, has become one of the most common approaches to crime reduction. A related geography-based approach is for municipalities to spend increased time cleaning up especially disordered areas of the city. This technique follows the “broken windows” hypothesis, which suggests that trash, graffiti, broken windows, and other signs of disorder suggest to would-be criminals that there is little law enforcement in the area, thereby making them more likely to commit a crime.
While several studies have suggested that these geography-based approaches are effective, it is difficult to study their full impact. While they may reduce crime in hot spots, they may also unintentionally encourage criminals to move to other, less-policed areas, leaving the overall level of crime in the city unchanged. This study is designed to contribute new evidence on whether hot spot policing and municipal clean-ups can reduce—rather than simply displace—crime.
Like in many major cities, crime in Bogotá, Colombia is spatially concentrated. Out of 136,984 street segments (a block of street between two intersections) in Bogotá, only 2,970 accounted for all homicides between January 2012 and September 2015. Other forms of crime are similarly clustered.
Safety and security for citizens in Bogotá has lagged behind the large improvements for those living in other areas of Colombia. In fact, Bogotá was deemed to have the third-worst quality of life in Latin America, surpassing only Guatemala City and Caracas, in a 2015 ranking by the Economist Intelligence Unit.
Researchers are working with Innovations for Poverty Action, Bogotá’s police department, and Bogotá’s mayor’s office to conduct a randomized evaluation to assess the impact of increased policing and municipal clean-ups on crime and citizens’ perception of the police. Researchers randomly assigned 1,919 of the highest-crime streets in Bogotá to four groups:
Hot spot policing: Police will increase the time they spend patrolling to around 90 minutes per day (up from the current average of 55 minutes), divided into 15-minute segments. Hot spots located near bars and night clubs will have three patrols during the day and three at night. Other hot spots will have five patrols during the day and one at night. Police will not alter any of their usual behavior or activity while patrolling these areas; they will only increase the amount of time they spend there.
Municipal clean-ups: Municipal teams will go to these areas to clean up the streets every few weeks. The teams will repair street lights, clear non-artistic graffiti, and collect garbage.
Hot spot policing and municipal clean-ups: Both municipal teams as well as police will spend more time in these areas.
Comparison: Police and municipal teams will not receive any special instructions about how to work in these areas.
In all 1,919 streets, researchers will use police reports and surveys to assess whether hot spot policing, municipal clean-ups, or the combination of the two changed crime rates or citizens’ perception of the police and city government. Furthermore, researchers will measure whether crime increased or decreased in areas adjacent to hot spot policing and municipal clean-up streets. This will allow them to determine whether the intervention simply displaced crime, moving it from one area to another, or whether it reduced the overall level of crime in the city.