Communities With Mass Shootings Share 4 Common Traits, Study Shows

"Communities need to modify the things that they can."


Mass shootings are senseless tragedies, but doctors suspect these events aren’t as random as they appear. And they’re wielding data to back up their claims.

In a presentation on Tuesday at the American College of Surgeons Clinical Congress 2018, Stephen Markowiak, M.D., presented an independent analysis of national data on the communities affected by mass shootings — shootings in which four or more people were killed — since 2005.

In the hopes that they could illuminate the common factors underlying mass shooting events, he and his colleagues matched up 155 mass shootings between 2005 and 2018 with data from the communities where they occurred.

By combing through 180 different data points on crimes and communities from the FBI, the CDC, and a dozen other datasets, the researchers revealed a handful of common factors across the communities.

Markowiak, who’s not just a surgical resident at the University of Toledo in Ohio but also a Masters of Public Health student, wants to specialize in trauma care. And while victims of mass shootings often end up in the care of trauma doctors, his interest in public health motivated him to investigate the attributes of a community that could lead to mass shootings in the first place.

“We’re trying to define the characteristics of the communities, and we’re really trying to generate a discussion,” Markowiak tells Inverse.

In the new study, his team found four main factors that are shared by communities where mass shootings take place.

Unsplash / Nik Shuliahin

1. Mental Health Care Access

Communities with mass shootings had more than twice as many mental health professionals per capita. There are a couple potential explanations for this.

“The communities where these mass shooting events take place are, in general, more urban,” Markowiak points out. Prior research has shown that rural areas face [significant shortages of mental health professionals]( compared to urban areas — not to mention the fact that urban areas typically are homes to wealthier, more educated individuals who are better equipped to access health care. More significantly, though, just because mental health providers are in a community does not mean that they are able to meet the needs of the community. Markowiak says that communities whose mental health care needs aren’t being met had significantly higher risks of mass shootings.

“It’s not just about providers per capita; it’s also about the needs of the community and matching that up,” says Markowiak.

Unsplash / Srecko Skrobic

2. Lack of Socialization Opportunities

The data shows the average person in communities with mass shootings associated with 10.5 to 11 people on a regular basis. In communities without mass shootings, the average was about 13. Strangely, the members of the communities with mass shootings also reported less physical activity in their free time despite having greater access to it.

Unsplash / Steve Knutson

3. Income Inequality

The national and community-level data revealed that communities with mass shootings had higher levels of income inequality, higher housing costs, and higher incidences of overcrowding and lack of utilities.

“Communities need to modify the things that they can,” says Markowiak. “They need to provide healthy, safe public spaces, and they need to take care of their people, in terms of their mental health, et cetera.”

Unsplash / xandtor

4. Stricter Gun Laws

Communities in states with the strictest gun laws had a 50-percent higher risk of mass shootings. But once the researchers adjusted for other factors besides just gun laws, they found that stricter gun laws, especially reporting to the National Instant Criminal Background Check System, were correlated with lower risks of mass shootings.

“After we adjusted for the community’s urban character, population density, the amount of men of a certain age within the community — things that the communities can’t change — it does appear that the state gun laws do have a correlation with a lower incidence of these mass shooting events,” says Markowiak.

“A cursory examination would lead to our initial conclusion: that places that have strong gun laws have higher incidences of mass shooting events,” he says. “But once you factor in the characteristics of the community, that changes. You should definitely want to live in a community that has stronger gun laws.”

Markowiak notes that these findings are just meant to provide a launch point for more research and discussion.

“This study is not powered to determine the cause,” he cautions. And while he’s alarmed, he’s not hopeless:

“I think that, based on the data we present, we would advise communities to make themselves generally healthier in terms of socioeconomic status, in terms of access to mental health services, increased socialization.”


Introduction: Mass shooting events (MSEs) have become highly politicized, complicating study and policy development. We sought to identify social determinants of health that put communities at risk for MSEs.
Methods: A dataset was created using the Federal Bureau of Investigation Uniform Crime Report, American Community Survey, state gun laws, the Behavior Risk Factor Surveillance System, and 10 other sources. Mass shooting events were defined as those events where 4 or more persons were killed. Mass shooting events were paired with 180 measures of social determinants of health for the county in which the shooting occurred. Pearson’s and Spearman’s correlation coefficients, t-tests, and chi-square tests were used to analyze the data set.
Results: A total of 93,380 instances of gun violence nationwide were identified from 2005 to 2018; 155 of these were identified as mass shootings. Communities in states with the strictest gun laws had a 1.513 greater risk (p = 0.031) of mass shootings. Communities with mass shootings averaged 2.139 times as many mental health professionals per capita (p < 0.001). Individuals in communities with MSEs were less social (2.67 fewer associations per person; p < 0.001) and demonstrated less leisure-time physical activity, despite a 32.4% greater access (p < 0.001). Communities with MSEs were, on average, 30.7% less rural (p < 0.001), 3.38 years younger (p < 0.001), had a 3.07% higher incidence of overcrowding or lack of utilities (p < 0.001), and had a higher ratio of income inequality (p = 0.001).
Conclusions: Communities at risk for mass shootings are identifiable. Communities seeking to safeguard citizens should focus on access to mental health professionals, promoting socialization and public space use, and addressing socioeconomic inequality.
Related Tags