What Has Been Learned?

While broad support for the pulling-levers approach may be justified

for many reasons, the committee found modest scientific evidence that

demonstrates whether these types of targeted policing programs can effectively

lower crime and violence. Clearly, there was pronounced and important

change in the youth homicide rate in Boston over the period of the

intervention, some of which was arguably due to Operation Ceasefire,

some due to secular changes in youth homicide, and some due to other (and

perhaps unknown) factors. The particular effects of this intervention, however,

are unknown. Furthermore, in the committee’s view, the existing data

and methods make it difficult to assess how Operation Ceasefire and other

similar policing programs affect crime. Researchers cannot hope to credibly

control for the many confounders that influence violence and crime using

simple time-series comparisons. With similar policing programs being

adopted in a number of other areas, there may be opportunities to combine

data from these sites to provide more persuasive estimates. Invariably,

however, researchers will be confronted with the fact that the programs

were not randomly adopted, the trends in violence are influenced by a

multitude of factors, and the dynamics of crime and violence are highly

complex.

The lack of research on this potentially important intervention is an

important shortcoming in the body of knowledge on firearms injury interventions.

These programs are widely viewed as effective, but in fact knowledge

of how, if at all, they reduce youth crime is limited. Without a much

stronger research base, the benefits and harms of these policing interventions

remain largely unknown. The committee recommends that a sustained

and systematic research program should be conducted to assess the

effect of targeted policing aimed at high-risk offenders. Additional insights

might be gained by using observational data from different applications,

especially if combined with thoughtful behavioral models of policing and

crime. An alternative means of assessing the impact of these types of targeted

policing interventions would be to run randomized experiments, similar

in spirit to those described above. Using this framework, one might hope

to disentangle the effects of the various levers and more generally assess the

effectiveness of these targeted policing programs.

10McGarrell and Chermak (2003) recently completed an unpublished study of the Indianapolis

pulling-levers intervention. Using time-series analyses, they found a 42 percent reduction

in homicides associated with the implementation of the intervention and found that

homicides were less likely to involve firearms, groups, and drugs.