So many guns, so little data: An economist on US gun violence

The Explainer

From President Donald Trump to presidential candidates, the air is thick with policy proposals to prevent the next mass shooting. Senate leaders promise to take up gun legislation when the Senate reconvenes in September. The House has already passed a universal background check bill that closes the “gun-show loophole.”

But there is a “shocking absence” of evidence to inform gun policy in the United States, and no conclusive evidence on what policies might effectively stop mass public shootings like those in El Paso, Texas, and Dayton, Ohio, according to Rosanna Smart, an economist with the Rand Corp. 

Last year, Rand published “The Science of Gun Policy,” a distillation of research on the effects of gun policies. The Monitor recently spoke with Dr. Smart, who is updating the report, to find out what is known about the effect of policies like “red flag” laws and what society might gain from more reliable data. The following is based on that conversation.

What is known about how to stop mass shootings?

All the evidence about gun policy and mass shootings is “inconclusive.” One reason is that the relative rarity of these instances makes them hard to study in a scientifically meaningful way. 

Also, researchers don’t have a common definition of a mass shooting, which makes it difficult to determine what would stop them. Not even the U.S. government defines the term, though the FBI says a “mass murderer” is someone who kills at least four people, not including himself or herself. [Editor’s note: The Monitor uses that definition.]

Depending on the various definitions, there were either seven, 65, 332, or 371 mass shootings in the U.S. in 2015, according to the Rand study.

Well, then, what is known about effective gun policies?

Of the many thousands of studies that Rand looked at, only 63 met its rigorous research criteria. Of those, it can be concluded that “safe storage” laws actually do reduce fatal firearm injuries to children and youths.

When it comes to background checks, “moderate” evidence suggests they reduce firearm suicides and firearm homicides, and “limited” evidence that they can lower overall suicide and violent crime rates, according to the Rand report. “Moderate” evidence also shows that laws banning guns from individuals with a history of involuntary commitment to a psychiatric facility do reduce violent crime. “Limited” evidence, meanwhile, points to reduced firearm suicides among youth when the minimum age for purchasing firearms is raised to 21.

Versions of all three of these policies are being talked about in the context of mass shootings, including “red flag” laws that allow the removal of weapons from people who may present a harm to themselves or others. But there is no conclusive evidence that these policy offshoots would be effective in stopping mass shootings.

On the side of gun advocates, “stand your ground” laws of self-defense may increase homicide rates, according to “moderate” evidence that Rand found. Quite a bit of research has been done on concealed carry laws, but it’s contradictory, says Dr. Smart. More research needs to be done on the effects of policies on the gun industry, hunting and sporting use of guns, and defensive use of firearms, the Rand report recommends.

What’s at stake for society given weak data on gun policy?

“I think we lose the ability to have conversations around gun policy that are grounded in science and that are grounded in fact,” says Dr. Smart. Lack of data makes it easier – or almost a necessity – to make claims about policy with no evidence to back them up. “It’s based largely on opinions or emotions.”

Conversely, sound data holds the promise of finding common ground in the divisive gun debate – though climate science denial shows how difficult that could be. Yet Dr. Smart is hopeful. In a survey of experts on both sides of the gun issue, Rand found general agreement that the primary objective of gun policy should be reducing homicides, suicides, and mass shootings. The two sides shared the same goal, even if they disagreed on how to get there.

“Providing evidence could potentially change minds,” says Dr. Smart. 

What are common misperceptions about mass shootings?

It comes back to the definition. Most people, when they hear of a mass shooting, probably think of public incidents in which people are shot at indiscriminately. But applying the commonly used definition of four fatalities casts a much wider net – including criminal activity, such as gang and robbery violence. 

“It’s easy to get kind of sucked into fear” about mass shootings, says Dr. Smart, but public shootings are “a small share of mass shootings, and a much smaller share of overall gun violence.”

The economist points to another misperception: the relationship between mental illness and mass shootings. “It gets brought up quite a bit and I don’t think the evidence is there to back it up.” Arguably, it could be said that a mass shooter is undergoing duress or has a behavioral problem, she says. But in terms of diagnosable mental illness, “that’s not from evidence.” 

How can gun policy research be strengthened?

One of the most effective ways would be for Congress to lift restrictions that limit federal research funding and access to data. In 1996, the National Rifle Association convinced Congress to cut funding for the Centers for Disease Control and Prevention. Before that, the CDC conducted millions of dollars in research on firearm violence. But when the federal agency found that having a gun at home increased the risk of homicide among household members, the CDC was seen as putting its thumb on the scale of gun control.

The ensuing budget cuts and conditions put a “chilling effect” on CDC firearms research, says Dr. Smart – and on the science of gun policy. “It seems kind of crazy that we don’t even know how many guns there are in America,” because the CDC no longer asks that question.

Universities and foundations have tried to take up the slack in funding and research at the CDC and other national entities, “but in terms of large-scale data collection, that’s something you need a lot of weight behind.”