Latest ‘mass shooting’ study strains credulity
The claims
In March 2025, the University of Colorado, Boulder (UCB) published a study claiming 1 in 15 U.S. adults had been on the scene of a mass shooting, and that 1 in 50 had been injured during a mass shooting in their lifetime.
Senior author David Pyrooz, who serves as a professor of sociology in the Institute for Behavioral Science at UCB, concluded:
“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.”
The headline and conclusion grab the attention of the casual reader and help reinforce the narrative that suggests gun violence in America is pervasive and inescapable. However, a more careful reading of the study is warranted.
The first thing that jumps out is the 1 in 15 claim. That would equate to over 18 million Americans over the age of eighteen supposedly being present at a “mass shooting” in their lifetimes. It just doesn’t pass the smell test. Looking at the source of the study’s data and the broad definitions used opens up the study and its conclusions to criticism.
The study didn’t analyze actual data from mass shootings, such as the number of people present or the number of people injured, but rather reported survey data from January 2024. The survey asked 10,000 respondents if they had ever been physically present on the scene or injured as a result of a mass shooting in their lifetime, and the study reported their answers.
The study defined a mass shooting as any gun-related crime where four or more people were shot in a public space — such as a school, shopping mall, workplace, or place of worship. It defined being present as being “in the immediate vicinity or where the shooting occurred at the time it occurred, such that bullets were fired in your directions, you could see the shooter, or you could hear the gunfire.” The study defined being “injured” as whether the respondent was physically injured in the incident, including being shot, trampled, or some other form of injury.
The purpose of the study was to determine the prevalence of direct exposure to mass shootings. In my opinion, the study failed to accurately determine the extent of direct exposure to such incidents but succeeded in feeding into the hypersensitive gun control debate.
To their credit, the study’s authors acknowledged the findings “are subject to well-known limitations of survey research.” They went on to note that “recall bias and cohort-specific experiences related to growing up in an era characterized by heightened awareness of gun violence could contribute to generational gradient observed.” In other words, people tend to exaggerate their connection to issues of heightened social awareness.
The math
A few mathematical equations expose how likely recall bias and exaggeration played a part in the study’s results. Follow along.
According to the U.S. Census Bureau, there were 266,000,000 adults (18+) in the US in 2024. 1 in 15 (present at mass shooting) equates to about 7% or 18,620,000. 1 in 50 (injured at a mass shooting) equates to about 2% or 5,320,000.
Determining the number of “mass shootings” that have occurred over the lifetimes of the current adult population is difficult to do with any accuracy.
One of the reasons for this is how the various databases that track “mass shootings” define what a mass shooting is. For the most part they use the general definition of “4 or more injured.” However, they widely differ on whether the incidents include all shootings (domestics, murder suicides, gang related shootings, officer involved shootings, defensive shootings, etc.) or if they tally shootings that are limited to the more traditional concept of a mass shooting – such as the shooting of innocents at a school, church, mall or other public venue.
The UCB study referred the more broadly defined scope of what a mass shooting is as captured in the Gun Violence Archive. This database estimates that there have been 5,000 mass shootings in the US in the past 10 years. Other data bases using a more traditional definition, such as the Associated Press’s mass shooting database, estimate there have been 285 mass shootings in the US in the past 10 years. The massive difference in estimates is obviously problematic to any consistent and meaningful evaluation of the issue.
Using the broader definition and liberally extrapolating the most recent 10-year data into a 50-year total of mass shootings results in an estimated 25,000 incidents. Even with this liberal estimation, if 7% of the current adult population claim they were present at one of them during their lifetimes, then an average of 745 adults would have been physically present at each of these incidents (18.6 M/25,000). If 2% of the current adult population claimed to have been injured during one of the mass shootings, then an average of 213 adults would have been injured as a result of each mass shooting over the past 50 years (5,3M/25,000). Unlikely.
Using the more conservative definition and extrapolating the most recent 10-year data into a 50-year total of mass shootings results in an estimated 1,425 incidents. Using this total, if 7% of the current adult population claim they were present at one of these shootings during their lifetime, then an average of 13,066 adults would have been physically present at each of these incidents (18.6M/1,425). If 2% claimed to have been injured during one of these mass shootings, then an average of 3,733 adults would have been injured during each of the mass shootings over the past 50 years (5,320,000/1,425). Even more unlikely.
Eyes on the ball
The gun violence problem in the United States is undeniable. However, distorting the problem and preying on fears of random and inescapable gun violence in mainstream America does not advance efforts to tackle the problems that are within our grasp to control — such as the use of firearms by repeat criminal offenders.