U.S. states with higher levels of gun ownership and those with fewer restrictions have higher rates of mass shootings, according to research published March 6 by The BMJ, a United Kingdom-based medical journal.
Researchers analyzed data related to firearm ownership, gun laws and mass shootings (defined as four or more persons killed by a firearm in a single incident) from 1998 to 2015.
Using a scale of restrictiveness published in the “Traveler’s Guide to the Firearms Laws of the Fifty States,” researchers found that for every 10-point drop in restrictions on gun ownership, there was an 11.5 percent higher rate of mass shootings.
Similarly, for every 10 percent increase in gun ownership levels, there was a 33.5 percent higher rate of mass shootings.
A chart provided in the appendix ranked states based on firearm ownership restrictions, finding that Massachusetts had the most limitations and Vermont the least over the time period analyzed.
An infographic offered a visual summary of the findings.
“The permissiveness or restrictiveness of state gun laws is associated with the rate of mass shootings in the U.S,” the report said. “States with more permissive gun laws and greater gun ownership have higher rates of mass shootings, and a growing divergence is noted in recent years as rates of mass shootings in restrictive states have decreased and those in permissive states have increased.”
The full report is available here.