Micro Places – Piza & O’Hara (2014)

Study Reference:

Piza, E. L., & O’Hara, B. A. (2014). Saturation foot-patrol in a high-violence area: a quasi-experimental evaluation. Justice Quarterly31(4), 693-718.

See also

Hatten, D., & Piza, E. L. (2022). When crime moves where does it go? Analyzing the spatial correlates of robbery incidents displaced by a place-based policing intervention. Journal of Research in Crime and Delinquency59(1), 128-162.

Location in the Matrix; Methodological Rigor; Outcome:

Micro places; General; Proactive; Moderately Rigorous; Mixed findings

What police practice or strategy was examined?

The study examined a saturation foot-patrol strategy that targeted street-level disorder and illicit narcotics trade in a violent area in Newark, NJ. A special unit comprised of 12 police officers and three supervisors was assigned to the target area to conduct patrol on foot on a nightly basis.

How was the intervention evaluated?

The intensive foot-patrol intervention within the quarter-mile target area was compared with less intensive (no extra officers were assigned) and intermittent enforcement in a control zone and standard responses to crime (e.g., routine patrol and ad hoc narcotics operations) in the rest of the precinct where the target area was located. Violent crime incidents (e.g., murder, shooting, and aggravated assault) before and during the intervention were compared in the treatment and control sites. A one-block catchment area surrounding the target site was included to measure displacement.

What were the key findings?

The target area outperformed the precinct control area (standard responses) on all crime measures, producing an overall violence reduction of 42% relative to the rest of the areas in the precinct. The operation sustained its positive effect when compared to the control zone (intermittent enforcement), although to a lesser extent. Evidence of both temporal and spatial displacement were found, but only for robbery, demonstrating the varying impact of saturation foot-patrol on different types of street violence.

What were the implications for law enforcement?

The authors suggest that while certain types of street violence, such as murder and aggravated assault, may be effectively addressed through foot-patrol, other violent crimes, such as robbery, might simply displace to other time periods or places. They suggest that police should design large-scale foot patrol initiatives in a manner that does not allow offenders, particularly robbers, to easily gauge the scope of the intervention and identify alternative crime opportunities.

Where can I find more information about this intervention, similar types of intervention, or related studies?