Terrorist bombings garner a lot of news coverage—but gun assaults are often more coldly efficient. Although firearms are used in only a small fraction of terror strikes, a recent study found that on a per-attack basis, guns are four times deadlier than other methods in high-income countries.

“What was surprising was the lethality of firearm attacks compared with other things like explosions and vehicles,” says lead author Robert Tessler, a senior fellow at the Harborview Injury Prevention and Research Center in Washington State. Tessler and his colleagues also found that guns are involved in a higher proportion of terror attacks in the U.S. than in other high-income countries. The findings add to an existing body of research that points toward the unique nature of gun violence in the U.S., where overall firearm deaths reached 36,000 in 2015.

After the recent terrorism incidents in San Bernardino, Orlando and London, Tessler wondered whether attackers' methods differed by region. He and his colleagues turned to the University of Maryland's Global Terrorism Database to analyze weapons used and fatalities in each of the 2,817 attacks carried out between 2002 and 2016 in the U.S., Canada, western Europe, Australia and New Zealand.

Credit: Amanda Montañez; Sources: “Use of Firearms in Terrorist Attacks: Differences between the United States, Canada, Europe, Australia, and New Zealand,” by Robert A. Tessler et al., in JAMA Internal Medicine. Published Online October 6, 2017; Global Terrorism Database www.start.umd.edu/gtd

Firearms were used in fewer than 10 percent of the attacks but accounted for 55 percent of fatalities, the researchers reported online in October in JAMA Internal Medicine. They found guns to be significantly deadlier than vehicular, explosive, biological, chemical or incendiary methods. The U.S. accounted for the greatest proportion of firearm attacks—20 percent—followed by the Netherlands, with 14 percent.

The authors did not factor gun ownership laws into their analysis, but other studies have indicated that tougher regulations are associated with fewer deaths. A 2017 review of nearly 50 years of scientific literature found that firearm homicide rates are lower in U.S. states with stricter gun control, and a 2014 study of a nationwide sample of all inpatient minors sent to hospitals for trauma revealed that children are safer in states with tighter firearm restrictions.

“I would encourage policy makers to consider this relationship between terrorism and firearms,” Tessler says, “not only as part of the national security policy agenda but also as part of the public health policy agenda.”