Researcher Douglas Wiebe first started studying gun violence as a doctoral student, investigating how having a firearm in one’s home affected the risk of injury. The work only heightened his interest in exploring gun violence from a public health perspective. Eventually, he decided to officially take on a question he’d been mulling over for almost a decade: Among people who’ve experienced a violent assault, are there any commonalities in their experiences just prior to the incident, and can we map those experiences in a way that reveals optimal intervention opportunities?

“I wanted to do a thorough job of measuring what people do and how they spent their time and see what might put people at risk,” Wiebe, an associate professor of epidemiology in the Department of Biostatistics and Epidemiology at the University of Pennsylvania Perelman School of Medicine, told me. “Getting injured can happen in the blink of an eye, but there must be some things that affect the likelihood.”

It turns out Wiebe’s hunch was correct. In a study published in the January issue of Epidemiology, Wiebe and his research colleagues mapped the paths and activities of more than 600 10- to 24-year-old boys and young men in Philadelphia — about 140 had experienced a gunshot wound, 206 had been assaulted with a different type of weapon, and about 280 had not been injured and served as the control group. Those who had been injured were recruited through the emergency departments of a pediatric hospital and adult trauma center in central Philly. Researchers asked the young men to recount the 24 hours before they had been injured (control subjects were asked to recall a random day within three days of the interview time). As Wiebe had hypothesized, researchers found that location and activity either protected study participants from assault or significantly increased the chance of assault. In addition, the study found a connection between the risk of violent assault and environmental characteristics that can easily be mitigated, such as greening vacant neighborhood lots.

While the idea that behavior and location affect the risk of assault is nothing new, this study is the first to go back and map a victim’s path in the hours before being injured and illuminate the environmental factors that if acted upon, could reduce risk and even prevent violence in the first place. And in a time when gun violence is never far from the front pages and any attempt at regulating firearm access seems politically hopeless, using data to find new avenues for gun violence prevention is exactly what public health does best.

“If you ask most people (where violence is likely to happen), they’d probably say the bad part of the city or in high-risk environments,” Wiebe said. “But what we’re finding is that it’s not who you are and where you wake up in the morning, but the point at which you’re assaulted. That really shifts the focus — no one is destined to meet violence.”

To reveal their findings, the researchers developed an original geography software application that maps each study participant’s activities and then superimposes it with a map of the environmental characteristics through which the participant traveled. Participants were mapped from the time they woke up on the morning of the assault to the point of assault — kind of like the person left a trail of tiny cookie crumbs as they moved throughout the day, as Wiebe described it. Those “cookie crumbs” were superimposed with 27 features of the built and social environment.

Here’s what Wiebe and his colleagues found: The risk of gunshot assault was higher when the person was alone, when it was raining, and when the person was outside and on foot, though lower when using the bus or trolley than when indoors. Risk of gun violence was higher in areas with lots of vacant properties, vandalism and violence, fire and police stations, and in areas with a high prevalence of household gun ownership. Risk of gun assault was also higher among those who had just acquired a firearm. The risk of gun assault was lower in areas with high levels of neighborhood connectedness. Risk of being assaulted with a weapon other than a gun was higher near recreation centers, in areas with high rates of vacancy, violence and vandalism, and among people who’d recently been drinking. Overall, researchers found that “engaging in certain activities and coming into contact with certain types of locations seemed to act as triggers that abruptly resulted in assault.”

Wiebe and study co-authors Therese Richmond, Wensheng Guo, Paul Allison, Judd Hollander, Michael Nance and Charles Branas write:

Of the numerous neighborhood conditions that we found to be associated with violence, we are most encouraged by identifying that structural features of the environment including recreation centers, alcohol outlets, and vacant properties were associated with a risk of violence. Others have suggested that each of these is potentially modifiable, and vacant properties in particular could be ameliorated with structural, scalable, and sustainable interventions that could help make neighborhoods safer.

“From a public health perspective, we know it’s quite hard to get people to change their behavior,” Wiebe told me. “So we’re much more optimistic that changes to the environment could have a more sweeping impact. …I do think that by starting to make structural changes, we can change the fabric of how these places are used and it’s by that process that we can hope to make places safer.”

Wiebe noted that while recruiting study participants, researchers learned that many had been assaulted in or around schools. Those young people were excluded from this study, as researchers wanted to zero in on community violence. However, Wiebe and his colleagues are now six months into a new study in which they’re using a similar mapping method to examine violent assault in school settings.

Wiebe noted that with so many Americans dying from gun violence, national decision-makers must free up research funds to study violence as a public health problem. And he added that a variety of sectors, from public health to community design to transportation planning, can play a role in violence prevention. Today, gun violence is the leading cause of death among 10- to 24-year-old young black men and boys, and the second leading cause of death within that age group overall.

“It’s time to talk about gun violence as a public health problem,” Wiebe told me. “It’s such a preventable problem.”

To read a full copy of the study, visit Epidemiology. For more on the benefits of structural change, check out this study on the connection between stress reduction and the greening of vacant urban lots.

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for nearly 15 years.