Deterring Gang-Involved Gun Violence: Measuring the Impact of Boston's Operation Ceasefire on Street Gang Behavior

The relatively weak quasi-experimental evaluation design of the original Boston Operation Ceasefire left some uncertainty about the size of the program's effect on Boston gang violence in the 1990s and did not provide any direct evidence that Boston gangs subjected to the Ceasefire intervention actually changed their offending behaviors. Given the policy influence of the Boston Ceasefire experience, a closer examination of the intervention's direct effects on street gang violence is needed. A more rigorous quasi-experimental evaluation of a reconstituted Boston Ceasefire program used propensity score matching techniques to develop matched treatment gangs and comparison gangs. Growth-curve regression models were then used to estimate the impact of Ceasefire on gun violence trends for the treatment gangs relative to comparisons gangs. This quasi-experimental evaluation revealed that total shootings involving Boston gangs subjected to the Operation Ceasefire treatment were reduced by a statistically-significant 31 % when compared to total shootings involving matched comparison Boston gangs. Supplementary analyses found that the timing of gun violence reductions for treatment gangs followed the application of the Ceasefire treatment. This evaluation provides some much needed evidence on street gang behavioral change that was lacking in the original Ceasefire evaluation. A growing body of scientific evidence suggests that jurisdictions should adopt focused deterrence strategies to control street gang violence problems.