The National Institute of Justice has been funding studies to try to find ways to reduce gun violence. I have found the report of one of these studies.
"This Research Report is part of the National Institute of Justice’s {NIJ’s) Reducing Gun Violence publication series. Each report in the series describes the implementation and effects of an individual, NIJ-funded, local-level program designed to reduce firearm-related violence in a particular U.S. city. Some studies received cofunding from the U.S. Department of Justice’s Office of Community Oriented Policing Services; one also received funding from the Centers for Disease Control and Prevention.
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The Research Reports should be of particular value to anyone interested in adopting a strategic, data-driven, problem-solving approach to reducing gun violence and other crime and disorder problems in communities.
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Analyses suggest that the Ceasefire intervention was associated with statistically significant reductions in all time series, including:
A 63-percent decrease in the monthly number of youth homicides in Boston.
A 32-percent decrease in the monthly number of citywide shots-fired calls.
A 25-percent decrease in the monthly number of citywide all-age gun assault incidents.
A 44-percent decrease in the monthly number of District B–2 youth gun assault incidents.
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Operation Ceasefire’s Working Group understood that law enforcement agencies generally do not have the capacity to “eliminate” all gangs or powerfully respond to all gang offending in gang-troubled jurisdictions. 28 Pledges to do so, although common, are simply not credible. The Working Group recognized that, for the strategy to be successful, a credible deterrence message must be delivered to Boston gangs. Because the Working Group could deploy, at best, only a few severe crackdowns at a time, the Ceasefire intervention targeted those gangs that were engaged in violent behavior rather than expending resources on those that were not. Through this focused application of deterrence principles, Operation Ceasefire suggests a new approach to controlling violent offenders."
Large PDF file
http://www.ncjrs.org/pdffiles1/nij/188741.pdfThe results highlighted above were achieved by enforcing existing laws, and a comprehensive effort to get to the root causes of gun violence in Boston.