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A memorial for victims of the King Soopers shooting in Boulder, which took place on March 22, 2021. (Credit: Glenn Asakawa/����ֱ�� Boulder)

����ֱ�� 7% of U.S. adults have been present at the scene of a mass shooting in their lifetime, and more than 2% have been injured during one, according to new ����ֱ�� Boulder research.

The study, published March 7 in the journal JAMA Network Open, also found that younger generations were significantly more likely to have been exposed than their parents or grandparents were.

Generation Z—adults born after 1996—were at greatest risk.

“This study confirms that mass shootings are not isolated tragedies but rather a reality that reaches a substantial portion of the population, with profound physical and psychological consequences,” said senior author David Pyrooz, a professor of sociology and criminologist in the Institute for Behavioral Science at ����ֱ�� Boulder. “They also highlight the need for interventions and support for the most affected groups.”

A ripple effect

For the study, Pyrooz and his colleagues surveyed a nationally representative sample of 10,000 adults in January 2024. (The researchers chose January because the month tends to see a lull in mass shootings.) They asked a series of questions, including: “Have you personally ever been physically present on the scene of a mass shooting in your lifetime?”

The group defined “mass shooting” as a gun-related crime where four or more people were shot in a public space. The researchers defined “physically present” as “in the immediate vicinity of where the shooting occurred at the time it occurred, such that bullets were fired in your direction, you could see the shooter, or you could hear the gunfire.”

Just under 7% of respondents answered yes. Just over 2% of respondents said they had been injured, which not only includes having been shot, but also hit by shrapnel, trampled by people fleeing the scene or other injuries.

“We are talking about one out of every 15 people in the United States,” said Pyrooz. “These are really high numbers for this seemingly unique and small subset of gun violence,” said Pyrooz.

While these numbers might seem high, Pyrooz said he was not surprised by the survey results. A single mass shooting can impact far more people than many realize.

For instance, during the 2017 shooting at the Route 91 Harvest Music festival in Las Vegas, the shooter killed 60 people and wounded 413 others. But another 454 people were injured during the ensuing panic as people fled to safety. In all, there were about 22,000 people at the concert—plus onlookers from surrounding hotels on the Las Vegas strip.

“That translates to about one out of every 11,000 Americans who were on the scene of that shooting alone,” said Pyrooz. “Continue that to other events that have occurred around the country and the numbers, unfortunately, add up.”

The ‘mass shooting generation’

Black people and males were more likely to have witnessed a mass shooting.

More than half of the respondents who had been present during a mass shooting said it happened in the last decade—a finding that reaffirms the notion that younger generations are experiencing a cultural phenomenon their parents didn’t have to deal with.

“Our findings lend credence to the idea of a ‘mass shooting generation,’” said Pyrooz. “People who grew up in the aftermath of Columbine have these unique experiences that are really distinguishable from the older population.”

Three-quarters of the respondents experienced mass shootings in their local communities—in places like bars or restaurants, schools, shopping outlets and synagogues.

The income and education level of respondents had no measurable impact on their chances of being present, or injured, at a mass shooting.

The aftermath

The study did not quantify how mass shootings impact mental health, but Pyrooz and his colleagues are publishing a forthcoming paper that will.

It found that about three-quarters of those who were present at the scene of a mass shooting but uninjured still experienced psychological distress, including fear, anxiety and depression. (For comparison, about 20% of people in the general population report these symptoms.)

Pyrooz hopes the ongoing research will help fill a research gap around the public health impacts of the relatively new, and understudied, phenomenon of mass shootings. He also hopes it will underscore the need to support programs aimed at reducing gun violence, and bolster supporting those suffering lingering effects from exposure.

He can still remember the sound of the sirens from the March 22, 2021, mass shooting at a King Soopers just miles from his office in Boulder.

He wasn’t personally exposed but knows what a toll it took on his own community.

“It’s not a question of if one will occur in your community anymore but when,” he said. “We need to have stronger systems in place to care for people in the aftermath of this tragic violence.”