Mass shootings in the United States


s are incidents involving multiple victims of firearm-related violence. The precise inclusion criteria are disputed, and there is no broadly accepted definition. 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, one study found that nearly one-third of the world's public mass shootings between 1966 and 2012 occurred in the United States. Using a similar definition, The Washington Post records 163 mass shootings in the United States between 1967 and June 2019.
Gun Violence Archive, frequently cited by the press, defines a mass shooting as firearm violence resulting in at least four people being shot at roughly the same time and location, excluding the perpetrator. Using this definition, there have been 2,128 mass shootings since 2013, roughly one per day.
According to some studies, the United States has had more mass shootings than any other country. Shooters generally either die by suicide afterwards or are restrained or killed by law enforcement officers or civilians. However, mass shootings accounted for less than two-tenths of 1% of all homicides in the United States between 2000 and 2016.

Definitions

There is no fixed definition of a mass shooting in the United States. The Investigative Assistance for Violent Crimes Act of 2012, signed into law in January 2013, defines a "mass killing" as one resulting in at least 3 victims, excluding the perpetrator. In 2015, the Congressional Research Service does not define a mass shooting but does define a public mass shooting—for the purposes of its report entitled “Mass Murder with Firearms”—as "a multiple homicide incident in which four or more victims are murdered with firearms, within one event, and in one or more locations in close proximity". The CRS further states that its report "attempts to refine the relatively broad concept of mass shooting into a narrower formulation: public mass shootings." A broader definition, as used by the Gun Violence Archive, is that of "4 or more shot or killed, not including the shooter". This definition, of four people shot regardless of whether or not that results in injury or death, is often used by the media, press, and non-profit organizations.

Frequency

Some studies indicate that the rate at which public mass shootings occur has tripled since 2011. Between 1982 and 2011, a mass shooting occurred roughly once every 200 days. However, between 2011 and 2014, that rate has accelerated greatly with at least one mass shooting occurring every 64 days in the United States.
In recent years, the number of public mass shootings has increased substantially, although there has been an approximately 50% decrease in firearm homicides in the nation overall since 1993. The decrease in firearm homicides has been attributed to better policing, a better economy and environmental factors such as the removal of lead from gasoline.

Differing sources

A comprehensive report by USA Today tracked all mass killings from 2006 through 2017 in which the perpetrator willfully killed 4 or more people. For mass killings by firearm for instance, it found 271 incidents with a total of 1,358 victims. Mother Jones listed seven mass shootings, defined as indiscriminate rampages in public places resulting in four or more victims killed, in the U.S. for 2015. An analysis by Michael Bloomberg's gun violence prevention group, Everytown for Gun Safety, identified 110 mass shootings, defined as shootings in which at least four people were murdered with a firearm, between January 2009 and July 2014; at least 57% were related to domestic or family violence.
Other media outlets have reported that hundreds of mass shootings take place in the United States in a single calendar year, citing a crowd-funded website known as Shooting Tracker which defines a mass shooting as having four or more people injured or killed. In December 2015, The Washington Post reported that there had been 355 mass shootings in the United States so far that year. In August 2015, The Washington Post reported that the United States was averaging one mass shooting per day. An earlier report had indicated that in 2015 alone, there had been 294 mass shootings that killed or injured 1,464 people. Shooting Tracker and Mass Shooting Tracker, the two sites that the media have been citing, have been criticized for using a broader criteria—counting four victims injured as a mass shooting—thus producing much higher figures.

Demographics

According to The New York Times, the majority of perpetrators they have published stories about are white males who act alone. According to most analyses and studies, the proportion of mass shooters in the United States who are white is slightly less than the proportion of white people in the general population of the US, however the proportion of male mass shooters is considerably greater than the proportion of males.

Contributing factors

Several possible factors may work together to create a fertile environment for mass murder in the United States. Most commonly suggested include:
  1. Higher accessibility and ownership of guns. The US has the highest per-capita gun ownership in the world with 120.5 firearms per 100 people; the second highest is Yemen with 52.8 firearms per 100 people.
  2. Mental illness and its treatment with psychiatric drugs. This is controversial. Many of the mass shooters in the U.S. suffered from mental illness, but the estimated number of mental illness cases has not increased as significantly as the number of mass shootings.
  3. The desire to seek revenge for a long history of being bullied at school and/or at the workplace. In recent years, citizens calling themselves "targeted individual" have cited adult bullying campaigns as a reason for their deadly violence.
  4. The widespread chronic gap between people's expectations for themselves and their actual achievement, and individualistic culture. Some analysts and commentators place the blame on contemporary capitalism and neoliberalism.
  5. Desire for fame and notoriety. Also, mass shooters learn from one another through "media contagion," that is, "the mass media coverage of them and the proliferation of social media sites that tend to glorify the shooters and downplay the victims."
  6. The copycat phenomenon.
  7. Failure of government background checks due to incomplete databases and/or staff shortages.
A panel of mental health and law enforcement experts has estimated that roughly one-third of acts of mass violence—defined as crimes in which four or more people were killed—since the 1990s were committed by people with a serious mental illness. However, the study emphasized that people with serious mental illness are responsible for less than 4% of all the violent acts committed in the United States.

Weapons used

Several types of guns have been used in mass shootings in the United States. A 2014 study conducted by Dr. James Fox of 142 shootings found that 88 were committed with handguns of all types; 68 with semi-automatic handguns, 20 with revolvers, 35 with semi-automatic rifles, and 19 with shotguns. The study was conducted using the Mother Jones database of mass shootings from 1982 to 2018. High capacity magazines were used in approximately half of mass shootings. Semi-automatic rifles have been used in six of the ten deadliest mass shooting events.

Deadliest mass shootings since 1949

The following mass shootings are the deadliest to have occurred in modern U.S. history. Only incidents with ten or more victim fatalities are included.
IncidentYearLocationDeathsInjuriesType of firearm usedRef
1Las Vegas shooting2017Paradise, Nevada58 851 Semi-automatic rifles, bolt-action rifle, and revolver
2Orlando nightclub shooting 2016Orlando, Florida49 58 Semi-automatic rifle and pistol
3Virginia Tech shooting 2007Blacksburg, Virginia32 23 Semi-automatic pistols
4Sandy Hook Elementary School shooting2012Newtown, Connecticut27 2Semi-automatic rifle and pistol
5Sutherland Springs church shooting2017Sutherland Springs, Texas26 20Semi-automatic rifle
6Luby's shooting 1991Killeen, Texas23 27Semi-automatic pistols
6El Paso Walmart shooting2019El Paso, Texas2323Semi-automatic rifle
8San Ysidro McDonald's massacre 1984San Diego, California21 19Semi-automatic carbine, pistols, and shotgun
9Stoneman Douglas High School shooting2018Parkland, Florida1717Semi-automatic rifle
10University of Texas tower shooting 1966Austin, Texas16 31Bolt-action rifle, semi-automatic carbine, revolver, semi-automatic pistols, and pump-action shotgun
11Edmond post office shooting1986Edmond, Oklahoma14 6Semi-automatic pistols
11San Bernardino attack2015San Bernardino, California14 24Semi-automatic rifles
11Fort Hood shooting2009Killeen, Texas1432 Semi-automatic pistol and revolver
14Camden shootings 1949Camden, New Jersey133Semi-automatic pistol
14Wilkes-Barre shootings1982Wilkes-Barre, Pennsylvania131Semi-automatic rifle
14Wah Mee massacre1983Seattle, Washington131Semi-automatic pistol and/or revolver
14Columbine High School massacre1999Columbine, Colorado13 24 Semi-automatic carbine, semi-automatic pistol, shotguns
14Binghamton shootings2009Binghamton, New York13 4Semi-automatic pistols
19Atlanta shootings1999Stockbridge and Atlanta, Georgia12 13Pistol
19Aurora theater shooting2012Aurora, Colorado1270 Semi-automatic rifle, pistol, and shotgun
19Washington Navy Yard shooting2013Washington, D.C.12 8 Semi-automatic pistol and shotgun
19Thousand Oaks shooting2018Thousand Oaks, California12 10+ Semi-automatic pistol
19Virginia Beach shooting2019Virginia Beach, Virginia12 4Semi-automatic pistols
24Easter Sunday massacre1975Hamilton, Ohio110Semi-automatic pistols and revolver
24Pittsburgh synagogue shooting2018Pittsburgh, Pennsylvania116 Semi-automatic rifle, semi-automatic pistols
26Palm Sunday massacre1984Brooklyn, New York100Semi-automatic pistols
26Geneva County massacre2009Geneva County, Alabama10 6Semi-automatic rifles, revolver, and shotgun
26Santa Fe High School shooting2018Santa Fe, Texas1014Shotgun and revolver