I researched the strictly tightened gun laws in Britain and Australia and concluded that they didn’t prove much about what America’s policy should be. Neither nation experienced drops in mass shootings or other gun related-crime that could be attributed to their buybacks and bans. Mass shootings were too rare in Australia for their absence after the buyback program to be clear evidence of progress. And in both Australia and Britain, the gun restrictions had an ambiguous effect on other gun-related crimes or deaths.

That’s … it. The original article at FiveThirtyEight, which Libresco again pointed me to in an email for her main source of data, cites a couple of real studies, but it only cherry-picked the more negative findings in the field. (Even then, one study cited found that Australia’s 1996 gun control law and buyback program was followed by a faster drop in gun deaths than would otherwise be expected; it’s just unclear whether the policy was the main cause.)

The rest of the article makes no attempt to raise any other actual empirical research, only citing a few statistics about the demographics of gun deaths.

Javier Zarracina/Vox

 
The US also has by far the highest number of guns in the world. Estimated in 2007, the number of civilian-owned firearms in the US was 88.8 guns per 100 people, meaning there was almost one privately owned gun per American and more than one per American adult. The world’s second-ranked country was Yemen, a quasi-failed state torn by civil war, where there were 54.8 guns per 100 people.

<img src="https://cdn.vox-cdn.com/uploads/chorus_asset/file/4120446/gun%20ownership.png" alt="Gun ownership by country.">

In short, America has the most gun deaths in the developed world, and the most guns period. What’s more, the research indicates these two issues are very much related.

The research is very clear: more guns mean more gun deaths

Going back to the Washington Post op-ed, Libresco argues that her research proved her initial bias — that gun control works — wrong.

But there have been much more thorough statistical analyses than what Libresco published at FiveThirtyEight or wrote about in the Washington Post. They all point to one fact: Gun control does work to save lives.

Last year, researchers from around the country reviewed more than 130 studies from 10 countries on gun control for Epidemiologic Reviews. This is, for now, the most current, extensive review of the research on the effects of gun control. The findings were clear: “The simultaneous implementation of laws targeting multiple firearms restrictions is associated with reductions in firearm deaths.”

The study did not look at one specific intervention, but rather a variety of kinds of gun control, from licensing measures to buyback programs. Time and time again, they found the same line of evidence: Reducing access to guns was followed by a drop in deaths related to guns. And while non-gun homicides also decreased, the drop wasn’t as quick as the one seen in gun-related homicides — indicating that access to guns was a potential causal factor.

Based on the other research, this actually isn’t a very surprising finding. Regularly updated reviews of the evidence compiled by the Harvard School of Public Health’s Injury Control Research Center have consistently found that when controlling for variables such as socioeconomic factors and other crime, places with more guns have more gun deaths.

“Within the United States, a wide array of empirical evidence indicates that more guns in a community leads to more homicide,” David Hemenway, the Injury Control Research Center’s director, wrote in Private Guns, Public Health.

For example, this chart, from a 2007 study by Harvard researchers, shows a correlation between statewide firearm homicide victimization rates and household gun ownership after controlling for robbery rates:

Social Science and Medicine

A more recent study from 2013, led by a Boston University School of Public Health researcher, reached similar conclusions: After controlling for multiple variables, the study found that a 1 percent increase in gun ownership correlated with a roughly 0.9 percent rise in the firearm homicide rate at the state level.

This holds up around the world. As Zack Beauchamp explained for Vox, a breakthrough analysis in 1999 by UC Berkeley’s Franklin Zimring and Gordon Hawkins found that the US does not, contrary to the old conventional wisdom, have more crime in general than other Western industrial nations. Instead, the US appears to have more lethal violence — and that’s driven in large part by the prevalence of guns.

“A series of specific comparisons of the death rates from property crime and assault in New York City and London show how enormous differences in death risk can be explained even while general patterns are similar,” Zimring and Hawkins wrote. “A preference for crimes of personal force and the willingness and ability to use guns in robbery make similar levels of property crime 54 times as deadly in New York City as in London.”

So America’s easy access to guns seems to lead to more gun violence and death.

But let’s focus on Australia and the UK in particular, since that’s what Libresco did in her Washington Post piece.

It is true that this is a difficult area to study. In part, that’s because these countries have such low homicide rates — to some degree because of previously existing, stricter gun control, criminal justice researcher Jerry Ratcliffe pointed out — that it’s going to be difficult to produce any statistically significant findings. It’s also difficult to wash out external effects, besides gun control, on gun deaths, even under the most statistically rigorous models.

The evidence from Australia in particular, though, is very suggestive. In her article for FiveThirtyEight, Libresco cited two studies — one from 2003 and another from 2016 — that found what she described as little evidence of the effectiveness of gun control. This seems to be true for the 2003 analysis. But the 2016 analysis is much more mixed, noting that there were faster drops in gun deaths after the buyback program was put in place, but failed to reach any hard conclusions because non-gun deaths also dropped more quickly (even more than gun deaths), suggesting that other variables were likely involved.

But this isn’t the only research into Australia’s laws. As my colleagues Dylan Matthews and Zack Beauchamp noted, other studies found positive impacts of the law. A review of the evidence by Harvard’s David Hemenway and Mary Vriniotis, for one, concluded that Australia’s law “seems to have been incredibly successful in terms of lives saved.”

A 2010 study by Andrew Leigh of Australian National University and Christine Neill of Wilfrid Laurier University also found that buying back 3,500 guns per 100,000 people correlated with up to a 50 percent drop in firearm homicides and a 74 percent drop in gun suicides. The drop in homicides wasn’t statistically significant, largely because the country’s gun homicide rate is so low that it’s hard to tease out even sharp drops with a lot of certainty. But the drop in suicides was statistically significant.

Most tellingly, Leigh and Neill’s study found that “the largest falls in firearm deaths occurred in states where more firearms were bought back.” Hemenway and Vriniotis reached similar conclusions in their review: “First, the drop in firearm deaths was largest among the type of firearms most affected by the buyback. Second, firearm deaths in states with higher buyback rates per capita fell proportionately more than in states with lower buyback rates.”

By homing in on individual states and types of guns, these studies provide a more rigorous and robust look at Australia’s law than a study like the 2016 analysis that Libresco cited, which broadly looked at nationwide data. And they conclude that the buyback program, along with other changes brought on by the 1996 law, reduced gun deaths.

But most importantly, this goes along with the rest of the evidence — including the extensive review published in Epidemiologic Reviews. When you put it all together, it’s hard to come to any conclusion other than gun control does, at least to some extent, reduce gun deaths.

Gun control can’t stop all violence. But it can help.

With that said, it’s probably true that this aspect of the gun control debate is not emphasized enough: Guns are a factor, not the only factor. Other factors include, for example, poverty, urbanization, and alcohol consumption.

But when researchers control for other confounding variables, they have found time and time again that America’s high levels of gun ownership are a major reason the US is so much worse in terms of gun violence than its developed peers — and stricter access to guns could help.

Another issue is that many of the policies researchers have studied seem to have, politically speaking, little to no chance in the US, at least at the federal level. Australia outright banned some types of guns, and set up a registry for all firearms owned in the country, required a permit for all new purchases. And, as if that wasn’t enough, its buyback program was mandatory — meaning you had to turn in your weapons, which is essentially government-mandated confiscation.

America can’t even get universal background checks through Congress. These much stricter measures have almost no chance of happening. That hinders the potential effectiveness of US laws: As Dylan Matthews explained, milder versions of gun control do have some evidence behind them in terms of reducing gun deaths, but they’re nowhere as strong as the effects seen with stricter policies.

It’s also true, as Libresco said on Twitter, that we could always use more research into gun policy (or, really, any policy issue). But the federal government has stifled gun research for years.

Still, the current research is clear: Gun control does cut down on gun deaths. A single data journalist’s look at some of the evidence doesn’t change that fact.