Total Homicide Rate
According to the evaluation by Papachristos, Meares, and Fagan (2007), the Chicago, Ill.–based Project Safe Neighborhoods (PSN) treatment districts experienced a statistically significant, 37 percent reduction in quarterly homicide rates during the observation period. Specifically, the average quarterly homicide rate decreased to 24.2 per quarter after PSN, compared with a rate of 38.2 before program implementation. The city as a whole and the control districts specifically experienced declines in the homicide rate during the intervention period, but these changes were modest in comparison with the reductions seen in the treatment group, and were not statistically significant.
The analysis of the impact of individual PSN strategies indicated that the use of offender notification forums had the largest impact on the overall reduction in the homicides. Additionally, the analysis indicated that federal Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) gun seizures were (modestly) significantly associated with a reduction in homicides. Prosecutions were modestly associated with a statistically significant decrease in total homicide (p=.030).
Gun-Related Homicide Rate
The analysis indicated that PSN treatment areas experienced a significantly significant reduction in gun-related homicides. The researchers found that areas with higher dosages of PSN strategies as a whole experienced statistically significant reductions in gun-related homicides.
Specifically, the analysis of the impact of ATF seizures indicated that the logged gun-related homicide rate decreased by nearly 2 percent for every 10 guns recovered in a beat. This translates into the logged gun homicide rate decreasing by about 18 percent for every 100 guns recovered. These results indicate the beneficial impact of multiagency gun recoveries in reducing gun-related offending. PSN prosecutions and offender notification forums were also statistically significantly associated with reductions in gun homicides.
Gang-Related Homicide Rate
The analysis indicated a statistically insignificant reduction of gang homicides in treatment district areas. The percentage of offenders who attended the offender notification forums was associated with a significant reduction (p<.001), and the number of prosecutions was also associated with a modestly significant reduction (p<.10).
Aggravated Assault/Aggravated Battery Arrest Rate
The analysis indicated a statistically significant modest reduction of aggravated battery/assaults in treatment district areas. None of the isolated PSN components were found to significantly affect the number of aggravated batteries.