The biggest questions about gun violence that researchers would still like to see answered

There are a few big things we know about gun violence in America: The US has way more guns per capita than any other country. It has far more gun homicides per capita than other wealthy countries. States with more guns have more gun deaths. And people with guns in their homes are more likely to be killed or to kill themselves with guns.

But just as importantly, there’s a lot that researchers still don't know. There’s frustratingly little evidence on what policies work best to reduce gun violence. (Australia saw a drop in homicides and suicides after confiscating everyone’s guns in the 1990s, but that would likely never happen here.) Experts still don’t have a great sense of what impact stricter background checks have, or how the "informal" gun trade operates, or even how people use guns in crimes.

"We have superficial knowledge of most gun violence topics," says Michael Nance, director of the Pediatric Trauma Center at the Children’s Hospital of Philadelphia. And this ignorance has serious consequences. It’s awfully hard to stop gun violence if we can't even agree on basic facts about how and why it happens.

This ignorance is partly by design. Since the 1990s, Congress has prevented various federal agencies from gathering more detailed data on gun violence. The Centers for Disease Control and Prevention (CDC), which has elaborate data gathering and monitoring programs for other public health crises like Ebola or heart disease, has been dissuaded from researching gun violence. The Bureau of Alcohol, Tobacco, Firearms, and Explosives can't distribute much of its trace data for research purposes. Obamacare limits doctors' ability to gather data on patients' gun use.

To get a sense of what we’re missing, I surveyed a number of researchers in the field and asked them about the most pressing questions about gun violence that they’d like to see answered. Here's what they said.

We still don’t know some very basic facts about gun violence in America

(Joshua Lott/Getty Images)

1) How are guns actually used? Tom Smith of NORC at the University of Chicago pointed out that "studying how guns are actually used in general" was a top research priority — including the question of how many people use guns for defensive purposes.

Other researchers pointed to related questions like: What percentage of gun owners even commit gun crimes? Why do gun accidents occur? Who's involved? Are criminals deterred by guns? These questions are a basic starting point.

2) Can we get better data on the victims of gun violence? Nance also pointed out that our data on the victims of gun violence leaves a lot to be desired. Researchers typically rely on death data ("one of the few known and reliable data points — you can’t hide the bodies," he says). But without more detailed data on who actually owns guns and who is exposed to guns, it can be hard to put these deaths in context.

And it would be good to have more detailed data on gun injuries that don't result in death. Daniel Webster, a professor of health policy and management at the Johns Hopkins Bloomberg School of Public Health, says, "We still don’t know nearly enough about nonfatal gunshot wounds, including how often they occur." That makes it much harder to get a full picture of gun violence.

3) What state laws, if any, work best to reduce gun violence? Michael Siegel, a professor of public health at Boston University, pointed to these three (broad) topics as the most pressing unanswered questions:

1. What state laws, if any, are effective in reducing rates of firearm violence?

2. Is there a differential impact of state firearm-related laws on homicide rates among white vs. African-American persons?

3. Are higher gun ownership levels related to higher firearm homicide rates because of a causal relationship or because people respond to high homicide rates by purchasing firearms?

There has already been some research on state-level gun control policies. For example, after Connecticut passed a law requiring gun purchasers to first obtain a license, one study found that gun homicides fell by 40 percent. When Missouri repealed a similar law, gun homicides increased by 23 percent. But, in part because they are retrospective and it’s impossible to run controlled experiments, studies like these remain hotly debated.

And there are all sorts of related questions here that (other) researchers would love to know the answers to. Do limits on high-capacity magazines reduce deaths? Do restrictions on alcohol sales make any difference? What about policies that make concealed carry licenses easier to obtain?

To really dig in, researchers would have to study state policies in far more detail. But, says Siegel, that will require need much better data than is currently on offer. He’d like to see more detailed state-level data on household gun ownership, on firearm policies, and on how well (or not) those policies are actually enforced.

4) How do people who commit gun crimes actually get access to their guns? Cathy Barber, who directs the Means Matter Campaign at the Harvard School of Public Health's Injury Control Research Center, listed these as big unanswered questions:

Pretty much every gun starts out as a legal gun. Among the guns that are actually used in crimes, how did they get there?

That is, how many are used by their initial legal purchaser and did that person pass a background check? If the gun was not used by the initial purchaser, how did it get to the person who used it in a crime? Straw purchase? Gun trafficking (buying in a state with lax laws and transporting for street sales in state with stricter laws)? Theft? (and what type of theft? Theft from individual homes or from gun shops or what? And if from people’s homes, do these tend to be unsecured guns kept for self-defense purchases – the gun in the bedside table?), etc., etc.

I think that both gun rights people and gun control people would be interested in the very specific answers to these questions and figuring out ways that we all could prevent the sort of cross-overs from legal to illegal possession and use.

A couple of other researchers agreed with this line of inquiry. Here’s Nance: "We need to know how weapons move in society to know how to best limit movement in the wrong direction (to those unfit to own)." And here’s Smith: "Understanding the ‘informal' gun market, that is guns that are acquired from others than licenses firearms dealers and therefore without background checks."

5) Is there any way to predict gun suicides? Nearly 21,000 people in the United States use guns to kill themselves each year, accounting for about two-thirds of all gun deaths. "We need to know more about how to predict who will commit suicide using a firearm," says Webster, "and ways to prevent [it]."

Back in 2013, a report from the Institutes of Medicine added some related questions around this topic that needed answering: Does gun ownership affect whether people kill themselves? And what's the best way to restrict firearm access to those with severe mental illnesses?

6) Does media violence have any impact on actual violence? This question came from Brad Bushman, a professor of communication and psychology at Ohio State University:

My research focuses on media violence. We know that youth who see movie characters drink alcohol are more likely to drink alcohol themselves. Similarly, we know that youth who see movie characters smoke cigarettes are more likely to smoke themselves. What about the impact of youth seeing movie characters with guns? Does exposure to movie characters with guns influence youth attitudes and behaviors about guns (e.g., do they think guns are cooler? are they more willing to own or use a gun? do they think guns make males more masculine?)?

7) What do we know about stopping mass shootings? I’ll add one more question to the list, which was considered a pressing research topic in the 2013 Institutes of Medicine report: "What characteristics differentiate mass shootings that were prevented from those that were carried out?"

One big reason current research into US gun violence is so dismal

(Kevin Cox/Getty Images)

It’s fair to call gun violence a public health crisis: Some 32,383 Americans were killed by guns in 2013. And for other health crises, like Ebola or heart disease, the CDC usually springs into action, by funding studies and research that look into the best policies to deal with the problem.

But that’s not really the case here. Back in 1996, Congress worked with the National Rifle Association to enact a law banning the CDC from funding any research that would "advocate or promote gun control." Technically, this wasn’t a ban on all gun research (and the CDC wasn’t doing advocacy anyway). But the law seemed vague and menacing enough that the agency shied away from most gun violence research, period.

Funding for gun violence research by the CDC dropped 96 percent between 1996 and 2012. Today, federal agencies spend just $2 million annually on gun violence prevention — compared with, say, $21 million for the study of headaches. And the broader field has withered over that period: Gun studies as a percentage of peer-reviewed research dropped 60 percent since 1996. Today there are only about a dozen researchers in the country whose primary focus is on preventing gun violence.

Private foundations and universities, such as the Johns Hopkins Bloomberg School of Public Health, have been partly able to pick up the slack, but private funders can rarely sustain the big, complicated data gathering and monitoring programs that the federal government can conduct. And that’s a problem because, as the researchers above noted, one of the biggest lacunae in gun research is data.

"If you look at other major public health issues, like Zika or Ebola or heart disease, the CDC is really a very authoritative source," says Andrew Rosenberg of the Union of Concerned Scientists. "Privately funded research can be helpful, but there’s no substitute for the CDC. They can do monitoring programs, long-term tracking, the stuff that’s hard to fund with a one-off grant from this or that foundation."

Siegel agrees: "The CDC has a critical role to play, so the first matter that needs to be resolved is restoring the CDC’s ability to conduct firearm-related research."

So will this situation ever change? After the Sandy Hook massacre in 2013, President Obama signed an executive order directing the CDC to start studying "the causes of gun violence." But very little has happened in the years since. The CDC didn’t actually budget. The problem, Rosenberg says, is that so long as that congressional amendment is in place, the CDC is unlikely to move forward.

Lately, there have been some calls to restore research. Republican Rep. Jay Dickey, who spearheaded the original CDC amendment, expressed remorse about the whole thing last year: "I wish we had started the proper research and kept it going all this time. I have regrets. … If we had somehow gotten the research going, we could have somehow found a solution to the gun violence without there being any restrictions on the Second Amendment."

Read more: What no politician wants to admit about gun control

We have a request

Vox's journalism is free because we believe that everyone deserves to understand the world that they live in. That kind of knowledge helps create better citizens, neighbors, friends, parents, consumers and stewards of this planet. In short, understanding benefits everyone. You can join in on this mission by making a financial gift to Vox today. Reader support helps keep our work free, for everyone. Will you join us?

One-Time Monthly Annual

$95/year

$120/year

$250/year

$350/year

Other

$

Yes, I'll give $120/year

Yes, I'll give $120/year

We accept credit card, Apple Pay, and Google Pay. You can also contribute via