The Effects of “Pulling Levers” Focused Deterrence Strategies on Crime
Authors: Braga Anthony A. , Weisburd David L. 
Published: October 2012

This Campbell systematic review assesses the effectiveness of focused deterrence strategies known as “pulling levels” in reducing crime. The review summarises findings from 10 studies, all of which report evidence from programmes in the US.

Pulling levers focused deterrence strategies are associated with a medium‐sized crime reduction effect. Nine out of 10 studies reported a statistically significant positive effect. There is a strongly significant medium size effect average effect across all studies.

Gang or group intervention programs had the largest effect, followed by the drug market intervention programs, with the smallest but still statistically significant effect for the high‐risk individuals programs.

All included studies use non‐randomized experimental designs, which have a risk of over‐stating impact. However, the effect size is large enough to have reasonable confidence in the effectiveness of these programs.

BACKGROUND

A number of American police departments have been experimenting with new problem‐oriented policing frameworks to prevent gang and group‐involved violence generally known as the “pulling levers” focused deterrence strategies. Focused deterrence strategies honor core deterrence ideas, such as increasing risks faced by offenders, while finding new and creative ways of deploying traditional and non‐traditional law enforcement tools to do so, such as directly communicating incentives and disincentives to targeted offenders. Pioneered in Boston to halt serious gang violence, the focused deterrence framework has been applied in many American cities through federally sponsored violence prevention programs. In its simplest form, the approach consists of selecting a particular crime problem, such as gang homicide; convening an interagency working group of law enforcement, social‐service, and community‐based practitioners; conducting research to identify key offenders, groups, and behavior patterns; framing a response to offenders and groups of offenders that uses a varied menu of sanctions (”pulling levers”) to stop them from continuing their violent behavior; focusing social services and community resources on targeted offenders and groups to match law enforcement prevention efforts; and directly and repeatedly communicating with offenders to make them understand why they are receiving this special attention. These new strategic approaches have been applied to a range of crime problems, such as overt drug markets and individual repeat offenders, and have shown promising results in the reduction of crime.

OBJECTIVES

To synthesize the extant evaluation literature and assess the effects of pulling levers focused deterrence strategies on crime.

SELECTION CRITERIA

Eligible studies had to meet three criteria: (1) the program had to have the core elements of a pulling levers focused deterrence strategy present; (2) a comparison group was included; (3) at least one crime outcome was reported. The units of analysis had to be people or places.

SEARCH STRATEGY

Several strategies were used to perform an exhaustive search for literature fitting the eligibility criteria. First, a keyword search was performed on an array of online abstract databases. Second, we reviewed the bibliographies of past narrative and empirical reviews of literature that examined the effectiveness of pulling levers focused deterrence programs. Third, we performed forward searches for works that have cited seminal focused deterrence studies. Fourth, we searched bibliographies of narrative reviews of police crime prevention efforts and past completed Campbell systematic reviews of police crime prevention efforts. Fifth, we performed hand searches of leading journals in the field.

DATA COLLECTION AND ANALYSIS

For our ten eligible studies, we complete a narrative review of effectiveness and a formal meta‐analysis of the main effects of these programs on reported crime outcomes.

MAIN RESULTS

Based on our narrative review, we find that nine of the ten eligible evaluations reported statistically significant reductions in crime. It is important to note here that all ten evaluations used nonrandomized quasi‐experimental designs. No randomized controlled trials were identified by our search strategies. Our meta‐analysis suggests that pulling levers focused deterrence strategies are associated with an overall statistically‐significant, medium‐sized crime reduction effect.

CONCLUSIONS

We conclude that pulling levers focused deterrence strategies seem to be effective in reducing crime. However, we urge caution in interpreting these results because of the lack of more rigorous randomized controlled trials in the existing body of scientific evidence on this approach.