Advocates for gun control are likely to seize on a new study showing the U.S. has experienced nearly a third of all public mass shootings worldwide over a nearly 50-year period, despite having only 5% of the world’s population.

Adam Lankford, a criminal justice professor at the University of Alabama, examined local police and federal law enforcement data from 1966 to 2012 and determined the U.S. had 31% of the world’s public mass shootings (those with four or more victims, according to the FBI’s definition). Over the course of 46 years, the U.S. experienced 90 such shootings.

A big takeaway from the study is that the U.S. could benefit from having fewer guns in circulation. Lankford found that the U.S. has “over 200 million more firearms in circulation than any other country,” he told Phys.org, so “it's not surprising that our public mass shooters would be more likely to arm themselves with multiple weapons than foreign offenders.”

“My study provides empirical evidence, based on my quantitative assessment of 171 countries, that a nation's civilian firearm ownership rate is the strongest predictor of its number of public mass shooters,” said Lankford. “Until now, everyone was simply speculating about the relationship between firearms and public mass shootings. My study provides empirical evidence of a positive association between the two.”

“The most obvious implication is that the United States could likely reduce its number of school shootings, workplace shootings, and public mass shootings in other places if it reduced the number of guns in circulation,” he added.

He pointed to Australia as an example. “From 1987-1996, four public mass shootings occurred in Australia,” Lankford said. “Just 12 days after a mass shooter killed 35 people in the last of these attacks, Australia agreed to pass comprehensive gun control laws. It also launched a major buyback program that reduced Australia's total number of firearms by 20 percent. My study shows that in the wake of these policies, Australia has yet to experience another public mass shooting.”

What did surprise Lankford was the U.S. had a lower average of victims in such shootings (6.87) compared to other countries (8.81).

The upside of America’s frequent mass shootings, according to Lankford, is that police get lots of experience dealing with and training for these incidents, which can help reduce the number of victims.

Following the U.S. at the top of the list of countries with the most public mass shootings is the Philippines (with 18 such shootings during the 46-year period), Russia (15), Yemen (11) and France (10). The five countries with the highest civilian firearm ownership rates—the U.S., Yemen, Switzerland, Finland and Serbia—are among the 15 countries with the most mass shootings. That suggests that “essentially you can’t be in the top five in firearm ownership and not have this problem,” Lankford told Newsweek.

The definition of “mass public shootings,” as used in the study, excludes incidents that involved robberies, drive-by shootings, hostage taking, or shootings that that were primarily gang-related or occurred in domestic settings.

It is the first quantitative analysis of all such reported shootings across the globe.

-Noel Brinkerhoff, Danny Biederman

To Learn More:

US Has Five Percent of World's Population, But Had 31 Percent of Its Public Mass Shooters from 1966-2012 (Phys.org)

Study: Mass Shootings ‘Exceptionally American Problem’ (by Stav Ziv, Newsweek)

As Mass Shootings Continue, Congress Remains Gun Shy about Enacting New Laws (by Noel Brinkerhoff, AllGov)