Correction: This article originally and incorrectly stated that the FBI defines a "mass shooting" as a single incident in which four or more people, including the gunman, are killed or injured by gunfire. Rather, this is the definition used by the Gun Violence Archive, a nonprofit group that verifies and compiles crowd-sourced incidents of gun violence in the United States, and whose data we use in the map below.
A gunman wielding an assault-type rifle and a handgun opened fire inside a crowded gay nightclub in Orlando, Fla. early Sunday morning, killing at least 49 people before dying in a gunfight with police. The incident is the deadliest mass shooting in American history.
This is the 133rd shooting of 2016 in which four or more people, including the gunman, have been killed or injured by gunfire during a single instance, according to the Gun Violence Archive, which categorizes such incidents as a "mass shootings."
Of the 133 incidents in 2016 listed on the GVA site, 11 resulted in the deaths of four or more people (including the gunman), 10 resulted in the deaths of three people and 14 resulted in the deaths of two people.
In fact, there has never been one officially accepted definition of a "mass shooting." And as the Washington Post notes: "The government has never even defined 'mass shooting' as a stand-alone category."
Critics say the Gun Violence Archive's definition is too lenient. They argue including injuries in the definition of a "mass shooting" artificially inflating the number of incidents, sending a message to the public that is both misleading and alarmist.