November 2011

U.S. Department of Justice Study on the Effectiveness of CeaseFire Chicago

Executive Summary of Evaluation

The Impact of CeaseFire

The report examines the impact of CeaseFire on shootings and killings. The first approach to this issue utilized statistical models to identify the effect of the introduction of the program on shootings and killings. These analyses employed 192-months (16 years) of data on selected sites and matched comparison areas to examine trends in violence. We also used crime mapping techniques to examine the impact of the introduction of CeaseFire on short-term trends in the micro-level distribution of shootings. Each CeaseFire site featured initially at least one “hot spot” of violent crime, and the analyses examined what happened to those hot spots over time in the program and comparison areas. Another statistical analysis focused on gang homicide. It utilized social network analysis to examine the effect of the introduction of CeaseFire on networks of within-gang and between-gang homicides, and the number of violent gangs active in the area.

… The time series analysis found positive results. In four sites it appears that the introduction of CeaseFire was associated with distinct and statistically significant declines in the broadest measure of actual and attempted shootings, declines that ranged from 17 to 24 percent. In four partially overlapping sites there were distinctive declines in the number of persons actually shot ranging from 16 to 34 percent.  These effects were assessed as “immediate and permanent” in five areas, and “gradual and permanent” in another program site.