What does the science show about guns in the US?

Guns are a fact of life in the US. I’m far from a gun nut, but growing up in small towns and traveling in rural areas, I have shot skeet, fired a .75-caliber flintlock rifle, hit targets with a .22, and even done a summer biathlon (in which you run, rather than ski). 

But as anyone who’s been watching the news knows, there’s a dark side to American gun culture. USA Today reports that as of early May, there had already been 202 mass shootings in 2023, with a total of 276 dead and 792 wounded. And that’s just the most visible problem. In 2021, the most recent year for which official data are available, the US saw a staggering 20,958 gun-related murders.

At that rate, the US is losing more people to gun violence every three years than its military lost in combat in the Vietnam War. 

One reason the US hasn’t been able to address this the way Australia did with its gun buy-back program in 1996 is that anything even remotely approaching the Australian solution runs afoul of the politically powerful National Rifle Association. 

The US is losing more people to gun violence every three years than its military lost in combat in the Vietnam War.

But a deeper issue is the Second Amendment to the US Constitution, which enshrines gun ownership only one step behind freedom of speech as a vital right, declaring: “…the right of the people to keep and bear Arms shall not be infringed.” 

According to one interpretation that means any “arms” you can bear (i.e. carry) is protected, even if nothing like it existed in 1791, when the Constitution was ratified. That’s a major problem, says John Donohue, an economist and law professor at Stanford University, because “no gun in 1791 could shoot 254 bullets through a wall and in a matter of seconds and kill people inside a church.” 

Donohue is one of a contingent of researchers who’ve dedicated years to doing what the US government was long unable to do because of legal roadblocks deterring its top public health agencies — the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health — from studying gun violence as a public health issue. 

One important academic finding was the discovery that when people buy guns, they increase the risk that someone in their own household will be shot, either with that gun or another. 

The latest and probably most definitive study on that comes from one of Donohue’s Stanford Law School colleagues, David Studdert, whose team published in the June 2022 issue of Annals of Internal Medicine: “[It] was a really good study that got incredible data,” Donohue says.

It drew on the fact that California requires gun buyers to provide their addresses, which could then be compared to the scenes of subsequent shootings. Even when the results were controlled for the overall dangerousness of the neighborhoods, Donohue says: “people living in the home were at higher risk of dying.” The victim, he adds, “was typically the wife or domestic partner of the guy who got the gun.”

When people buy guns, they increase the risk that someone in their own household will be shot, either with that gun or another. 

Donohue’s own research has focused on the larger question of what happens to gun violence when states adopt more permissive gun laws, as compared to states that are more restrictive. 

Like Studdert’s study, this type of work presents massive data problems, but early this year, Donohue and other researchers in the field appear to have won big parts of the debate.

Policy analysts at the RAND Corporation became convinced that at least three types of gun policy affected gun violence. These were: (a) restrictions on children’s access to parents’ firearms; (b) permissive concealed carry laws; and (c) “stand your ground” laws (which allow people to use lethal force in situations in which they still had the opportunity to safely retreat). The first, the RAND Corporation report concluded, reduced gun violence; the other two increased it. 

Meanwhile, Donohue’s team has been looking into why permissive gun laws are linked to increased rates of gun violence. One reason, they concluded in an as-yet-unpublished study, is that such laws appear to massively increase the number of guns finding their way into the hands of street gangs and other criminals. 

The reason? Because criminals are adept at stealing guns. 

“Gun thefts rise very substantially when right-to-carry laws go into effect,” Donohue says, “in part because people leave them in their cars.” In fact, all too often they leave them in unlocked cars. “We have information about gangs telling 12-year-old kids to go through parking lots and collect guns from unlocked cars,” he says.

Overall, his data shows that right-to-carry laws may be infusing an extra 100,000 stolen guns into the criminal world every year. 

Other researchers are also looking for ways to carry gun-policy research beyond the simple realm of statistical correlation and into the more difficult realm of trying to puzzle out why one thing appears to be linked to another. 

It is well known, for example, that gun sales often soar in the wake of highly publicised mass shootings. But why? 

Right-to-carry laws may be infusing an extra 100,000 stolen guns into the criminal world every year

One possibility is that people are suddenly more afraid of becoming the next victim. But it turns out that that’s not the primary motivation, says Maurizio Porfiri of New York University’s Tandon School of Engineering. In a 2020 paper in the journal Patterns, his team compared these spikes in gun sales to the type of media attention each mass shooting received and concluded that they are driven not so much by fear of being the next victims, but by fear of regulations that might restrict the ability to buy a gun (i.e. people are rushing out to buy guns now, while they can, before their right to do so could be stripped away).

In other work, Porfiri has looked for ways to cope with the long delay in the release of official gun violence data by developing a model to predict it from more readily available information, such as the number of federal background checks and what’s happening both on Twitter and in more conventional media. “We were able to show that you can actually do it,” he says. 

Not that it’s simple. Porfiri’s research is funded by an engineering program in the National Science Foundation, and is designed to use complex mathematical techniques to take an engineering-style approach to what is generally viewed as a social-science problem. 

Most recently, he and researcher Rayan Succar, also of Tandon School of Engineering, took a look at one of the deadliest types of mass shootings: those conducted by people whose primary goal is fame.

In a recent paper in Proceedings of the National Academy of Sciences, they and other colleagues examined headline-grabbing mass shootings over the course of 55 years, and concluded that fame-seeking shooters tend to target unexpected victims in unusual settings, hoping to create an effect his team was able to quantify as “surprisal”. 

The antidote? Don’t give such shooters the fame they are seeking. “No notoriety,” Porfiri says. 

That means not just minimising use of the shooter’s name—which some in the US are already doing — but revealing as few details about the attack as possible.

“Given that they are seeking fame by innovation,” Porfiri says, “you don’t want to go into too many details.” 

For a public clamoring to know what happened and why, that, of course, is anathema. But if you want to reduce the incentive for future fame-seeking attacks, Porfiri says, it is what the science shows. “That is something many scholars are advocating for,” he says, “[and] this provides additional backing to that.”

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