Evidence-Based Policing Matrix
Groups – Braga (2008)
Study Reference:
Location in the Matrix; Methodological Rigor; Outcome:
Groups; Focused; Highly Proactive; Moderately Rigorous; Effective
What police practice or strategy was examined?
The study examined a pulling levers strategy (Operation Peacekeeper) in Stockton, California implemented in 1997 that focused on a small number of gang members responsible for the bulk of the city’s gun violence problem. The Stockton Police Department (SPD) conducted intensive analyses to identify key offenders, groups, and behavior patterns, and then formed an interagency working group in collaboration with various government and community-based organizations. They reached out directly to active gangs and delivered the message that any outbreaks of gun violence would trigger intensive law enforcement efforts on the entire gang; they provided targeted gang-involved youth with meaningful resources and opportunities to escape the gang lifestyle; and they launched federal prosecutions when gang violence occurred, which resulted in the prosecution of core street gang members.
How was the intervention evaluated?
The study used a time series design to analyze the impact of Operation Peacekeeper program on gum homicide in Stockton. It examined the citywide gun homicide rate by month from January 1990 to December 2005. In addition, the study used a quasi-experiment design comparing gun homicide trends in Stockton to those in eight other midsize cities in California from January 1990 to December 2004.
What were the key findings?
The study found that the Operation Peacekeeper pulling levels strategy was associated with a significant reduction in gun homicides in Stockton. The average monthly count of gun homicide incidents in Stockton decreased by approximately 35% during the intervention and remained low after the intervention ceased. None of the other eight cities experienced a significant crime drop during the intervention period.
What were the implications for law enforcement?
The author suggests that a pulling levers strategy combining problem-oriented and community-based approaches can be effective in controlling violent offenders and reducing gun violence.
Where can I find more information about this intervention, similar types of intervention, or related studies?