We know far too little about almost every subissue in the gun discussion. We don’t know whether the federal assault weapons ban—it only lasted 10 years, from 1994 to 2004—had any effect on mass killings. We don’t know the effect of most individual gun laws, in part because the effect is probably small, since the laws are often so minor or full of loopholes.

In terms of homicide, we know that a gun in the house is bad for women, but is it bad for men? There are few convincing studies. While women are usually murdered at home, often with the gun that’s in the home, men are mostly killed outside the home, with somebody else’s gun. Which leads to the question: What is the effect of carrying a hidden gun or of concealed-carry laws? If I’m walking around with a hidden gun, does that put me at lower risk because I can defend myself, or at higher risk because I put myself in more dangerous situations? We don’t know.

We lack good data on nonfatal shootings. We know very little about gun theft or gun training, about gun storage or gun shop practices, about the effect of guns on college campuses or guns at work. The list goes on and on.

There is a dearth of research because there’s a dearth of funding. The Centers for Disease Control and Prevention largely shut down its small firearm research funding beginning in 1996, when the National Rifle Association persuaded Congress to cut the agency’s funding if the agency did anything the gun lobby might possibly construe as promoting gun control. The National Institutes of Health has funded little gun research. The National Institute of Justice supports only a tiny amount. Private foundations haven’t stepped up. No one wants the hassle. This lack of funding hits hard in soft-money schools like ours.

There’s no question that if there were no mental health problems, if no one had anger or alcohol problems, we’d have less violence. If we had less poverty and inequality, we’d have less violence. If we didn’t have racial tensions, we’d have less violence. If we had better education and better parenting, we’d have less violence. But the fact is, we also have a gun problem.

Look at any other developed country. They do much better than we do at preventing gun violence. It’s not that they have fewer mental health problems or fewer violent video games or less moral decay. It’s not that they are less violent or less crime-prone. It’s that with stronger gun laws—with universal background checks and waiting periods and sometimes even notifying a spouse or ex-spouse that someone is planning to get a gun—they’ve made it much harder for the wrong people to gain access to guns.

It used to be that after a mass shooting—Columbine, for example—I’d get phone calls from reporters for two days. Then I wouldn’t hear from anybody until the next mass shooting. Now reporters email and call me all the time: ‘I’m doing this article on this aspect of the gun problem. What does the science say?’ Mostly I tell them, ‘Well, there’s one study, and it’s not quite on point, but at least it’s something.’ It’s frustrating not to have the data, but I’m encouraged by the drumbeat of media coverage. Reporters are staying interested. Gun violence prevention isn’t new, but it’s finally considered news.”