In America, mass shootings dominate headlines, framed by statistics and brief moments of “thoughts and prayers”. Yet behind the numbers lies an even more unsettling reality: nearly 7% of U.S. adults have been directly exposed to a mass shooting.

Not just hearing about it. Not just knowing someone affected. Physically present. Seeing the shooter, hearing gunfire, or having bullets fired in their direction. The figure is even higher for those in Gen Z.

Millions Have Witnessed a Mass Shooting

In the study, senior author David Pyrooz, a professor of sociology and criminologist at the Institute for Behavioral Science at CU Boulder surveyed a nationally representative sample of 10,000 adults in January 2024. The findings surprised even him.

A whopping 7% of Americans have been present at a mass shooting. This was defined as being “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.”

“It does surprise us, though the reach of mass shootings is pretty extensive. For instance, about 1 in 11,000 American adults were on the scene of the Harvest 91 shooting in Las Vegas. That’s obviously an extreme example, but illustrates how direct exposure can balloon to 7 percent,” Pyrooz told ZME Science.

Yes, the study authors say some large events skew the data.

“We would expect this to be the case. Though any mass shooting near crowded bars, shopping malls, or other locations is likely to drive high levels of direct exposure.”

This doesn’t make the data misleading — it makes it more urgent, Pyrooz says. Mass shootings with large crowds amplify the number of people affected, pushing the reach of gun violence beyond what many policymakers and the public might assume.

More Than Just a News Story — A Daily Reality

Since 2020, the U.S. has seen over 500 mass shootings annually, contributing to a total of approximately 5,000 mass shootings over the past decade.

Despite being perceived as isolated tragedies — school shootings, attacks in theaters, or violence at large gatherings — the data tells a different story. Pyrooz notes that 35% of mass shootings occur in neighborhoods, challenging the common perception that such events primarily take place in public venues. In other words, the trauma of a mass shooting isn’t tied to a single event. It’s embedded in the streets people walk on every day.

The study also found that exposure is not evenly distributed across demographics. Younger people, men, and Black Americans were significantly more likely to report having witnessed a mass shooting. The researchers suggest that lifestyle patterns and systemic factors may contribute to these disparities.

This is an important find. Mass shootings don’t happen in a vacuum; they intersect with existing social structures. Understanding why certain demographics are at higher risk could guide efforts to reduce exposure and trauma.

What Can Be Done?

Pyrooz emphasizes that the study didn’t look at policy interventions or solutions for this crisis. He also mentions that while according to the survey, 2% of Americans were injured during a mass shooting, this wasn’t directly due to the shooting.

“Our estimate of physical injury was particularly surprising, though the definition we used included any range of injuries, from a bullet hitting flesh to getting hurt fleeing the scene.”

Researchers who study the root causes of mass violence have increasingly called for a public-health approach to gun violence — one that targets risk factors just as we would for any other widespread health threat. While the social, psychological, and environmental contributors to mass shootings are complicated, numerous studies suggest that effective prevention hinges on a combination of interventions tailored to individuals, institutions, and policies.

One line of evidence points to the importance of early mental health interventions. Psychiatric epidemiologists have shown that preventive therapy — particularly cognitive behavioral therapy, crisis counseling, and wraparound community programs — can reduce the likelihood that people who exhibit early warning signs progress to violent behavior. Research groups at universities such as Johns Hopkins and the University of Michigan have published data highlighting how targeted support for individuals in crisis may head off violent acts before they occur.

Scientists have also explored how certain gun-safety measures can contribute to a decline in mass shootings. Studies evaluating the impact of background checks and waiting periods, for instance, have found correlations between stricter requirements and lower rates of firearm-related fatalities. Experts stress that these steps alone are not panaceas. Rather, they are part of a larger effort to regulate firearms in ways that minimize the risk that dangerous individuals can access lethal weapons.

Crucially, none of these measures exist in a vacuum. Early mental-health support, community outreach, and evidence-based firearm regulations reinforce each other. Studies suggest that this multi-pronged approach — much like efforts to curb infectious diseases — can reduce both the frequency and the severity of mass shootings.

“Our findings highlight the substantial reach of mass shootings in US society. This widespread exposure underscores the need for comprehensive public health strategies to address the broad and enduring impacts of mass shooting exposure,” researchers wrote in the paper.

The study was published in JAMA.