More than half of all mass shootings in the U.S. since 1966 have taken place in the last 20 years.
From 2014 to 2022, the U.S. saw around 4,000 mass shootings, resulting in around 21,000 deaths or injuries, according to a study published Wednesday in the journal JAMA Network Open.
The study analyzed data from the Gun Violence Archive, a research database that tracks gun violence incidents based on reports from media outlets, local or state police departments and other government agencies. It defines a mass shooting as one in which four or more people, not including the shooter, are shot or killed.
Louisiana had the highest rate of mass shootings per capita of any state, the study found: around 4.3 shootings for every 100,000 people. The rate in Washington, D.C., was even higher — 10.4 shootings for every 100,000 people — though it is a city, not a state.
Hawaii and North Dakota were the only two states that did not see any mass shootings over the nine years studied.
Leslie Barnard, the study’s author and a doctoral student at the Colorado School of Public Health, said her research team initially suspected that Colorado would rank higher on the list.
“It was right after the Club Q shooting and someone asked, ‘Why is Colorado so much higher in mass shootings than other states?’” Barnard said, referring to the mass shooting at a gay nightclub in Colorado Springs last November that killed five people and injured 17 others. But as it turned out, she added, Colorado’s rate of mass shootings is “right in the middle” nationally.
Overall, mass shooting rates were highest in Southeastern states such as Alabama, Kentucky, Maryland, Mississippi, South Carolina and Tennessee.
Barnard’s research found that social-related mass shootings — those that occurred at a bar, club or house party — were the most common category, making up around 27% of mass shootings from 2014 to 2022. Another 16% were crime-related, meaning they involved gangs, drugs, armed robbery, carjacking, murder, suicide or home invasion.
Domestic violence, including kidnapping, made up 11%, and around 1% were related to school or work. But Barnard said the domestic violence shooting numbers are likely undercounts because many such incidents aren’t reported to the police. A 2021 study found that 59% of fatal mass shootings from 2014 to 2019 were related to domestic violence.
On the whole, mass shootings aren’t easy to define or categorize, said Ali Rowhani-Rahbar, an epidemiology professor at the University of Washington who studies violence prevention.
“The border between these categories may be more porous than it may appear,” Rowhani-Rahbar said. “For example, a shooting in a bar or in a club that you may consider social may have some relationship with a domestic violence dispute.”
But certain interventions can reduce the prevalence of mass shootings, no matter the category, he said. Rowhani-Rahbar pointed to red flag laws as one example, which allow a state court to order the temporary removal of firearms from a person who poses a danger to themselves or others.
In regards to policies associated with more mass shootings, he said, “there is no doubt that looser gun laws have been shown over and over, time and time and time again, to be associated with higher rates of different forms of gun violence.”
That may partly explain why mass shootings are concentrated in the Southeast, he said, and why Hawaii — a state with one of the lowest rates of household gun ownership — recorded no mass shootings.
As for North Dakota, Rowhani-Rahbar said, “the population there is not very large.” (The state’s population is about 780,000, according to the U.S. Census.)
Overall, the U.S. saw 14.6 gun deaths — including accidents, murders and suicides — per 100,000 people in 2021, according to a Pew Research Center analysis of data from the Centers for Disease Control and Prevention.
Among all types of gun violence, Barnard said, mass shootings are still relatively uncommon, so it’s not surprising that some states would see very few.
Media coverage of mass shootings “creates this idea that these are very, very common,” she said, but “compared to any other type of shooting event, like suicide, homicide, it is extraordinarily rare.”
Randi Selvey contributed.
