From 2004 to 2006, the city of Boston experienced notable increases in violent crime, especially robberies and assaults committed with guns. The majority of the violence was concentrated in disadvantaged, predominately minority neighborhoods. In December 2006, Edward Davis was appointed Commissioner of the Boston Police Department (BPD); he immediately set about addressing the spike in violent crime. Commissioner Davis developed the Safe Street Team (SST) strategy through which police officer teams were assigned to 13 different violent crime hot spots. The SSTs applied problem-oriented, community-policing strategies to identify and address recurring problems in their target areas.
In 2009, the BPD received funding from the Bureau of Justice Assistance’s Smart Policing Initiative (SPI) to conduct an ex-post facto evaluation of the place-based SST strategy. The Boston SPI project was composed of a process evaluation of the actual work carried out by SST officers, a 28-year longitudinal analysis of the stability of violent crime hot spots in Boston, and an impact evaluation of the SST strategy using a nonrandomized quasi-experimental design that matched the 13 SST target areas with comparable violent crime hot spots throughout the city. The evaluation showed that violent crime hot spots in Boston have been remarkably stable over time. The SST officers deployed nearly 400 different situational/ environmental, enforcement and community/social service interventions in the 13 targeted hot spots during the study period. The impact evaluation showed that the SST strategy was associated with a 17.3 percent reduction in the total number of violent index crimes, a 19.2 percent reduction in the number of robberies, and a 15.4 percent reduction in the number of aggravated assaults—with no evidence of displacement or diffusion effects.
Although it is best to include evaluation as a part of the planning, development, and implementation of police programs, the Boston SPI experience showed that rigorous, retrospective evaluation can still be carried out effectively. The Boston SPI team successfully addressed the challenges associated with building a solid, after-the-fact program evaluation, and the study produced findings that are of considerable value to BPD and other law enforcement agencies across the United States.