Neighborhood – MacDonald et al. (2016)

Study Reference:

MacDonald, J., Fagan, J., & Geller, A. (2016). The effects of local police surges on crime and arrests in New York City. PLoS one11(6), e0157223.

Location in the Matrix; Methodological Rigor; Outcome:

Neighborhood; General; Proactive; Rigorous; Mixed effects

What police practice or strategy was examined?

Operation Impact in New York City involved two primary components. First, the police identified crime hot spots and designated these as impact areas that would receive a surge of police presence. Second, once additional police were deployed to these areas, they were encouraged to conduct investigatory stops (i.e., stop, question, and frisk) to enforce misdemeanor infractions. Investigatory stops included those based on probable cause of involvement in crime or general suspicion based on observed behavior. Additional police officers sent to these areas were new academy graduates.

How was the intervention evaluated?

The intervention occurred from 2004-2012. The police department identified high crime areas to receive the intervention and 75 of the city’s 76 precincts had at least one impact area during this timeframe. The impact on reported crimes and arrests in the designated areas were evaluated by comparing the difference in the reported crime and arrest rates before and after an area was designated as an impact zone compared to areas in the same police precinct that were not designated as an impact zone.

What were the key findings?

Impact zones were associated with a statistically significant 12% reduction in total reported crime, relative to control. Robbery and burglary incidents experienced the largest crime reduction effects, though there was also evidence of spatial displacement of robbery offenses into nearby areas. Crime reduction effects appeared to be limited to probable cause stops, however, which represented a minority of total stops conducted. Stops based on general suspicion produced no overall significant impact on reported crime.

What were the implications for law enforcement?

These findings indicate that police stop activity concentrated in high-crime areas can be an effective crime deterrent. However, this deterrent effect may be limited to stops based on probable cause. As implemented in Operation Impact, the justification for investigatory stops was overly broad, resulting in an abundance of stops that may have been ineffective in terms of crime control. These results further support the position that more stringent standards for investigatory stops should be followed, resulting in fewer overall stops but a higher percentage of stops that are linked to crime prevention.

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