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Groups – McGarrell et al. (2006)

Study Reference:

McGarrell E. F., Chermak S., Wilson, J., & Corsaro, N. (2006). Reducing homicide through a “lever-pulling” strategy. Justice Quarterly, 23(2), 214-231.

Location in the Matrix; Methodological Rigor; Outcome:

Groups; Focused; Highly Proactive; Moderately Rigorous; Effective

What police practice or strategy was examined?

This study examines a “pulling levers” strategy implemented in Indianapolis, as part of the Indianapolis Violence Reduction Partnership (IVRP). The key components of the IVRP included a multi-agency working team, collaboration with a research partner, and application of formal problem-solving techniques to the homicide and gun assault problem. The interventions targeted illegal gun carrying and use among known groups of chronic offenders, often involved in the drug trade. A key component of the implemented strategy were “lever-pulling” monthly meetings, which involved face-to-face meetings with groups of high-risk probationers and parolees in which criminal justice officials and community members described their concerns to these individuals, followed by promises to follow through with severe penalties if these individuals became involved in firearms possessions on future gun crimes. Probationers and parolees were urged to take advantage of a range of services and opportunities including mentoring from ex-offenders, employment, housing, substance abuse, education, and vocational training. Additionally, in the Brightwood neighborhood of the city, a crackdown in the form of gang arrests and prosecutions occurred during the intervention period, and this was exploited by members of the IVRP to accomplish its objective of communicating a “zero tolerance of violence” message to the offending population.

How was the intervention evaluated?

The authors employed time-series analyses of the trends in homicide across Indianapolis as well as in comparison cities. The comparison sites (Cincinnati, OH, Cleveland, OH, Columbus, OH, Kansas City, MO, Louisville, KY, and Pittsburgh, PA) were chosen based on their Midwestern location and population. Homicide data were obtained using the Supplementary Victim-Level Homicide Database and collected from January 1, 1997 to June 30, 2001 yielded a total of 54 months.

What were the key findings?

At the time of the intervention, monthly homicides declined significantly by 34.3%, and this reduction was sustained over the evaluation period. When compared to the homicide trends in six other cities, Indianapolis was the only one that experienced a statistically significant change. Additionally, the impact was greatest during the month following the Brightwood gang crackdown.

What were the implications for law enforcement?

The authors argue that this study and others suggest that problem-solving approaches that employ research-practitioner partnerships can be effective ways to implement pulling levers approaches.

Given the threats to single-city evaluations of multiple component interventions, caution is appropriate in interpreting the results of the present study. On the other hand, the results are consistent with other studies and promising in terms of the potential for reducing homicide.

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