Mass shootings in the United States

Mass shootings are incidents involving multiple victims of firearm related violence. Definitions vary, with no single, broadly accepted definition.^[1][2][3] One definition is an act of public firearm violence—excluding gang killings, domestic violence, or terrorist acts sponsored by an organization—in which a shooter kills at least four victims. Using this definition, a 2016 study found that nearly one-third of the world's public mass shootings between 1966 and 2012 (90 of 292 incidents) occurred in the United States,^[4][5] In 2017 The New York Times recorded the same total of mass shootings for that span of years.^[6] A 2023 report published in JAMA covering 2014 to 2022, found there had been 4,011 mass shootings in the US, most frequent around the southeastern U.S. and Illinois. This was true for mass shootings that were crime-violence, social-violence, and domestic violence-related. The highest rate was found in the District of Columbia (10.4 shootings per one million people), followed by Louisiana (4.2 mass shootings per million) and Illinois.^[7]

Perpetrator demographics vary by type of mass shooting, though in almost all cases they are male. Contributing factors include easy access to guns, perpetrator suicidality and early childhood trauma, as well as various sociocultural factors including online media reporting of mass shootings. In one study, 44% of mass shooters had leaked their plans prior to committing the act.

The Federal Bureau of Investigation designated 61 of all events in 2021 as active shooter incidents.^[8] The United States has had more mass shootings than any other country.^{[4][9][10][11][12]} After a shooting, perpetrators generally either commit suicide or are restrained or killed by law enforcement officers. Mass shootings accounted for under 0.2% of gun deaths in the United States between 2000 and 2016,^[13] and less than 0.5% of all homicides in the United States from 1976 to 2018.^[14]