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Member Research & Reports

Member Research & Reports

Columbia: States with Permissive Gun Laws Have Higher Mass Shooting Rates

States with more permissive gun laws and greater gun ownership have higher rates of mass shootings, and a growing divide is emerging between states with restrictive versus permissive gun laws. Researchers at Columbia University Mailman School of Public Health found that in most years permissive states had higher mass shooting rates compared to restrictive states. The results showed that a 10 percent higher state firearm ownership rate was associated with a 35 percent higher rate of mass shootings. The findings appear online in the British Medical Journal.

“U.S. gun laws have become more permissive in past decades, and the divide between permissive states and those with more stringent laws seems to be on the uptick in concert with the growing tragedy of mass shootings in the U.S.,” said senior author Dr. Charles Branas, chair and Gelman Professor in the Department of Epidemiology. Lead author Mr. Paul Reeping, also in the Department of Epidemiology, said “Our study sets the stage for figuring out which specific gun laws could be most impactful in reducing mass shootings”

Mass shootings were defined as events in which four or more individuals were killed by a firearm using data from the FBI’s Uniform Crime Reporting System (UCR). The researchers used a restrictiveness-permissiveness scale of U.S. state gun laws, which gives a rating between 0 and 100 for the firearm laws of all 50 states.

“More studies that test the impact of specific state gun laws are warranted given our findings, the general increase in state gun law permissiveness, and the pressing need to stem the continued and increasing tragedy of mass shootings in the U.S.,” said Mr. Reeping.

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