There Have Been 352 Mass Shootings in 336 Days-Disputed!

There Have Been 352 Mass Shootings in 336 Days-Disputed!

Summary of eRumor:
There are reports that there had been 352 mass shootings in the U.S. by December 2015, more mass shootings than days in the year so far.
The Truth:
Claims about the number of mass shootings reported in the U.S. vary because the definition of “mass shooting” is disputed.
After Syed Rizwan Farook and Tashfeen Malik allegedly murdered 14 people and injured 21 in San Bernardino on December 2, 2015, reports spread across social media that there had been 352 mass shootings in the first 336 days of 2015, more mass shootings than days. That figure comes from, a reddit community project that collects and archives reports of shootings in the U.S.
The group defines “mass shooting” as one in which at least four people are injured. Various government agencies define mass shootings differently.
The FBI doesn’t have a specific definition for “mass shooting.” It defined a “mass killing” as one with at least three fatalities in a 2014 report on active shooters. The FBI defines “mass murder” as one in which at least four people are killed at one time. The Congressional Research Service defined “mass shooting” as one in which at least four people are killed with a gun, meeting the FBI’s definition of “mass murder,” according to a report released in July 2015.
Brock Weller, a co-founder of, explained that the group defines a mass shooting as one in which four people are injured — not killed — because it would be “absurd” not to call 18 people being shot a mass shooting. In an interview with The Trace, a nonprofit that focuses on coverage of guns in the media, Weller explained:

“The goal is to stop minimizing these acts of violence,” Weller explains. The site’s authors point to a 2012 shooting in which one person was killed and 18 people were wounded at a nightclub. Because only one person died, it was not considered a mass shooting. This June, 10 people were shot at a block party on a basketball court in Detroit; the next day, 11 were wounded when two people opened fire with a shotgun at a block party in West Philadelphia. Neither were widely referred to as mass shootings.

“Arguing that 18 people shot during one event is not a mass shooting is absurd,” the Tracker’s founders write. Medical advancements have helped save lives that would have otherwise been lost, a fact Weller believes the gun lobby benefits from. “Those gunshot victims are still just as shot and will never be the same,” he says.

So, using’s definition for mass shootings, there had been 352 mass shootings by early December, an average of more than one mass shooting per day at that point. Using the Congressional Research Service definition for mass shootings, however, there had been far fewer than 352 mass shootings. That’s why we’re classifying this one as disputed.