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Neighborhood – Saunders et al. (2015)

Study Reference:

Saunders, J., Lundberg, R., Braga, A.A., Ridgeway, G., & Miles, J. (2015). A synthetic control approach to evaluating place-based crime interventions. Journal of Quantitative Criminology, 31(3), 413–434.

Location in the Matrix; Methodological Rigor; Outcome:

Neighborhood; Focused; Highly proactive; Rigorous; Effective

What police practice or strategy was examined?

This study examined the effectiveness of the High Point Drug Market Intervention (DMI), a place-based focused deterrence strategy, on reducing disorderly narcotics sales and violence by drug sellers in illicit overt drug markets. DMI aims at shutting down overt drug markets entirely. The intervention, with individual overt drug markets as the unit of work, employs a joint police-community partnership to pinpoint individual offenders, inform them of the consequences of continued illegal dealing in a call-in meeting, offer supportive services via a community-based resource coordinator, and deliver rigid community norms against illegal drug dealing. The intervention also aims to create informal social control from immediate family or community figures to pressure drug dealers to stop offending by organizing and focusing services, help, and support for them.

How was the intervention evaluated?

The intervention was implemented in five different drug markets in High Point, North Carolina. This study employed a synthetic control method to create comparison areas matched with the targeted areas on reported crime and arrest rates for various offenses and a range of demographic variables. The synthetic control quasi-experimental approach is useful here, because the drug market sites are unique (i.e., they are the highest drug locations in the city), and so finding comparison areas is challenging. But by combining different areas of the city weighted to be as similar to targeted drug markets as possible, reasonable comparison sites can be generated. The effects of the interventions were estimated for each target area on crime incidents, violent incidents, drug crimes, and calls for service. Meta-analysis was then conducted to combine the results across areas. The study also examined whether the intervention led to activities associated with one drug market being displaced to other drug market sites.

What were the key findings?

In the year following each DMI, calls for service decreased by 16% and violent crimes decreased by 34% on average in the treatment markets, whereas all crimes and drug crimes initially increased and then dropped with no net effect compared to the synthetic control markets. For five years following the intervention, both drug and overall crime continued to decrease, with a 20-30% reduction in crime rates and a 50% decrease in reported drug crime rates compared to the synthetic control markets. The study noted larger effect sizes of the intervention compared to a previous evaluation of the same intervention using less rigorous research methods.

What were the implications for law enforcement?

The study suggests that DMI, a focused deterrence program, can effectively reduce multiple crime types in drug markets without displacing them to nearby drug markets. In particular, the authors suggest that the full effect of the DMI does not appear immediately after the intervention but grows over time – in some cases, for several years. The authors also suggest innovative quasi-experimental approaches, such as the synthetic control model, may be especially useful for evaluating strategies when finding a reasonable comparison area is challenging because the target site is unique.

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