Were you floored by the finding that we've had more mass shootings than days this year? So was Mark Follman. According to Mother Jones, where Follman is an editor, there have been only four mass shooting this year—including the one in San Bernardino—and only 73 since 1982. Why the discrepancy? "The answer is that there is no official definition for 'mass shooting,'" Follman writes at the New York Times. The popular shootingtracker.com, for instance, labels a mass shooting as any incident involving four people who have been injured or killed—meaning that a late-night shooting in Savannah, Ga., that injured three and killed one on the same day as the San Bernardino massacre is included. But Follman says that's problematic. "While all the victims are important, conflating those many other crimes with indiscriminate slaughter in public venues obscures our understanding of this complicated and growing problem."
That's why Mother Jones' tally includes only attacks in which four or more people were killed, like the FBI's. However, it excludes murders linked to robberies, domestic abuse, and gang violence. This outline helped Follman realize that "the more narrowly defined mass shootings have grown more frequent, and overwhelmingly involve legally obtained firearms," he says. "Everyone is desperate to know why these attacks happen and how we might stop them—and we can't know, unless we collect and focus on useful data that filter out the noise." Jodi Upton at USA Today offers a similar view. "The problem is one of definitions, sometimes used sloppily and interchangeably," she writes. "The result: a very confused, and possibly hyperventilating public." Read Follman's full piece here and Upton's here. (Read more mass shootings stories.)