After a dramatic decrease in violent crime throughout the 1990s, the city of Boston (Massachusetts) witnessed a sudden rise in the number of violent index crimes (including murder, forcible rape, robbery, and aggravated assault) from 2004 to 2006. Violent index crimes rose by 9 percent during those years, while the number of homicides jumped by 23 percent. In response to the spike in violence, in 2007 the Boston Police Department (BPD), led by a new commissioner, implemented a place-based, problem-oriented policing strategy called Safe Street Teams (SST).
The SST program was designed to reduce violent crime by assigning teams of BPD officers to targeted crime hot spots around the city and requiring them to implement problem-oriented policing strategies to address specific violence-related problems at each site. Officers assigned to the SSTs were tasked with modifying the place characteristics, situations, and dynamics that promoted violence in the targeted areas.
The BPD used mapping technology (ArcGIS 9) as well as violent index crime data for the 2006 calendar year to identify 13 violent crime hot spot areas that SST officers would target. The 13 hot spots covered only 6.1 percent of Boston’s street geography but experienced 23.1 percent of the city’s violent index crimes in 2006. The targeted areas of Boston were Orchard Park, Grove Hall, Codman Square (B3), Upham’s Corner, Eagle Hill, Codman Square (C11), Bowdoin/Geneva, Franklin Field, Downtown Crossing, Heath/Centre Street, Lower Roxbury/S. End, Morton/Norfolk, and Tremont/Stuart.
There were 13 SSTs stationed at hot spots around the city. Each SST consisted of a sergeant and six patrol officers. The SSTs were responsible for employing community- and problem-oriented policing techniques, such as the SARA (scanning, analysis, response, and assessment) model. All team members went through in-service training that concentrated on the specific programming of the SST as well as problem-oriented policing more generally. SST officers were required to stay in their assigned areas unless an emergency call required their involvement.
There were almost 400 distinct problem-oriented policing strategies that were implemented by SST officers in the crime hot spots. The strategies fell into three broad categories:
- Situational/environment interventions that were designed to change the underlying characteristics and dynamics of the places that were believed to be linked to violence. Examples of these activities include removing graffiti and trash, adding or fixing lighting, removing abandoned vehicles, installing a CCTV system, evicting problem tenants, repairing sidewalks, and giving out crime prevention literature.
- Enforcement interventions that were meant to arrest and deter individuals that were identified as committing violent crime or contributing to a disorderly atmosphere at the targeted areas. Examples of these kinds of activities include focused enforcement efforts on drug-selling crews, street gangs, robbery crews, public housing trespassers and unregulated vendors, and burglars/shoplifters, as well as focused efforts on indicators of social disorder (public drinking, loitering, etc.).
- Community outreach/social service interventions that were supposed to stimulate community involvement in crime prevention and address problematic behaviors by disorderly individuals at the places (such as local youth with no recreational opportunities). Examples of these activities include providing new recreational opportunities for youth (i.e., basketball leagues), partnering with local agencies to provide needed social services to youth, working with clinicians to provide street outreach to the homeless, and planning community events (i.e., block parties).
Overall, Braga, Hureau, and Papchristos (2011) found mixed results when evaluating the crime control benefits of Safe Street Teams (SST). The results showed that the SST intervention was associated with significant reductions in total violent index crimes, robberies, and aggravated assaults over the 10-year study period; however, there were no significant reductions in homicides and rape/sexual assaults.
Total Violent Index Crime
The SST intervention was associated with a statistically significant 17.3 percent reduction in the number of total violent index crime incidents (which include homicide, rape/sexual assault, robbery, and aggravated assault) at the treatment street units relative to the comparison street units.
The SST intervention was not associated with a statistically significant reduction in the number of homicide incidents at the treatment street units relative to the comparison street units.
The SST intervention also was not associated with a statistically significant reduction in the number of rape/sexual assault incidents at the treatment street units relative to the comparison street units.
Relative to the comparison street units, the SST intervention was associated with a statistically significant 19.2 percent reduction in the number of robbery incidents at the treatment street units.
Finally, the SST intervention was associated with a statistically significant 15.4 percent reduction in aggravated assault incidents at the treatment street units relative to the comparison street units.
Displacement and Diffusion
The analyses revealed that all of the violent index crime categories did not experience significant displacement or diffusion effects as a result of the SST intervention. Total violent index crime, homicide, rape/sexual assault, and robbery incidents experienced nonstatistically significant decreases in the treatment two-block catchment areas relative to the comparison two-block catchment areas. Aggravated assault incidents experienced nonstatistically significant increases.