Neighborhood – Papachristos et al. (2007)
Location in the Matrix; Methodological Rigor; Outcome:
Neighborhood; Focused; Highly Proactive; Moderately Rigorous; Effective
What police practice or strategy was examined?
This study examines Project Safe Neighborhoods (PSN) in Chicago, which focused on three broad goals: (1) reduce demand among young gun offenders, (2) reduce supply by identifying and intervening in illegal gun markets, and (3) prevent onset of gun violence. Specifically, this study assesses the impact of four of Chicago’s PSN strategies—increased federal prosecutions for convicted felons carrying or using guns, lengthy sentences associated with federal prosecutions, supply-side firearm policing that increased the rate of gun seizures, and social marketing of the deterrence and social norms messages through offender notification meetings. The offender notification meetings were designed to stress to offenders the consequences should they choose to pick up a gun and the choices they have to make to ensure that they do not reoffend.
How was the intervention evaluated?
This study uses a quasi-experimental design to assess the impact of Chicago’s PSN strategies. Treatment and control districts were selected nonrandomly (growth curve modeling and propensity scores were used to adjust the nonrandom allocation) from the city’s 25 police districts based mainly on the concentration of homicide and gun violence. Two adjacent police districts were selected as PSN treatment districts and two others were used as near-equivalent control groups. The units of analysis are 54 police beats (24 treatment beats and 30 control beats), each approximately one square mile and with approximately 7,600 residents. Outcome measures of lethal and nonlethal criminal violence included homicides and aggravated batteries and assaults.
What were the key findings?
Overall, the treatment districts experienced a 37% drop in quarterly homicide rates during the observation period. The average quarterly homicide rate decreased from 38.2 to 24.2 per 100,000, per quarter after PSN was implemented. The largest effect was associated with the offender notification meetings that . stress individual deterrence, normative change in offender behavior, and increasing views on legitimacy and procedural justice. During the same period, the city as a whole and the control districts also experienced a decline in homicide, though it was less pronounced.
What were the implications for law enforcement?
One of the main goals of PSN was to alter the structures of such networks by altering normative perceptions of gun use and spreading information about its potential consequences. Program initiatives such as the forums and school-based programs are specifically geared toward this end. The diffusion of the PSN message through offender forums might be utilizing the tight network of interaction and communication among offenders, especially gangs and phenomenon commonly found in the diffusion of information in a market.
Where can I find more information about this intervention, similar types of intervention, or related studies?
- All studies in the Matrix on neighborhoods
- Focused deterrence studies in the Matrix
- One pager – Impact of PSN on Violent Crime
- One pager – PSN A national strategy to locally address gun violence
- CrimeSolutions Focused Deterrence Practice Profile
- Pulling Levers Systematic Review
- COPS Officer Pulling Levers Review
- Project Safe Neighborhoods – Bureau of Justice Assistance
- Project Safe Neighborhoods – Michigan State University