The Data Are Pointing to One Major Driver of America’s Murder Spike

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After murders in the United States soared to more than 21,000 in 2020, researchers began searching for a definitive explanation why. Many factors may have contributed, such as a pandemic-driven loss of social programs and societal and policing changes after George Floyd’s murder. But one hypothesis is simpler, and perhaps has significant explanatory power: A massive increase in gun sales in early 2020 led to additional murders.

New data from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) suggest that that indeed may have been the case. According to the data, newly purchased weapons found their way into crimes much more quickly and often last year than in prior years. That seems to point to a definitive conclusion—that new guns led to more murders—but the data set cannot prove that just yet.

The ATF data are the result of tracing nearly 400,000 firearms in 2020. According to the bureau, firearms are traced only “at the request of a law enforcement agency engaged in a bona fide criminal investigation where a firearm has been used or is suspected to have been used in a crime.” Not all guns recovered by law enforcement are traced, and many guns that are used in crimes are never recovered by law enforcement to begin with. But the ATF’s data are the most robust source available for evaluating the increased use of firearms in the United States in 2020.

What’s most startling in these new data is the degree to which firearms purchased in 2020 featured in crimes committed in 2020. The ATF’s data set includes a measure known as the “time to crime” of each gun traced—the time from when a firearm was legally purchased to when it was recovered after a crime. On this metric, an enormous shift is apparent: The number of traced guns whose time to crime was a year or more increased by less than 1 percent in 2020 compared with 2019, but the number of guns whose time to crime was six months or less increased by 90 percent.

Prior years looked quite different. Only about 13 percent of guns traced from 2015 to 2019 were recovered within six months of purchase. In 2020, 23 percent were. In total, the average time to crime fell from 8.3 years in 2019 to seven years in 2020, and just about half of the guns traced in 2020 crimes were purchased three or more years prior to recovery, compared with more than 70 percent a decade ago. Moreover, states with greater upticks in gun background checks—meaning more purchases of new guns—also saw greater increases in new guns recovered in and traced to crimes. All told, what this reveals is that guns used in crimes in 2020 were newer than in the past. Additionally, more guns were recovered in 2020 than in 2019 across a host of crimes. “You do see these guns ending up in risky situations more quickly than in the past,” says Aaron Chalfin, a criminology professor at the University of Pennsylvania.

No data exist on exactly how many guns were sold in 2020. The best proxy is the number of firearm background checks performed by the FBI, which indicates an attempted purchase but doesn’t necessarily mean a completed one. These background checks surged dramatically in 2020, first when coronavirus cases began to appear in the U.S. and again after Floyd’s murder at the end of May. Background checks remained remarkably high for the first few months of 2021 but came down a bit during the second half of the year.

As clear as the link between new guns and gun violence appears, the difficulty comes in trying to show a connection to the rise in homicides specifically, as the ATF’s data do not enable the sort of precision researchers would need to confirm that link.

The ATF's data do not specify time to crime for the subset of firearms that were recovered in homicides; everything is grouped together and cannot be disaggregated. As a result, there’s no way to say for certain that newly purchased guns helped fuel the homicide spike. Less than 3 percent of the guns traced in the 2020 data set were connected to homicides. Moreover, there is no discernible relationship between where the murder rate rose in 2020 and where more new firearms were recovered and traced: States with large increases in firearm recoveries were no more likely to see an increase in murder than states with small increases in firearm recoveries. Ultimately, more granular data would be needed to answer with perfect confidence the crucial question of whether new guns lead to more homicides, but there is also no reason to suspect that guns used in homicides differ significantly from guns used in other kinds of crimes.

The ATF’s data are kludgy in part because of legal limitations, specifically a law known as the Tiahrt Amendment. “The Tiahrt Amendment is basically a law that says the ATF cannot provide gun-level trace data to anyone other than the police,” says Cassandra Crifasi, a researcher of gun-violence prevention and policy at Johns Hopkins University. “What that means is that researchers are restricted to the sort of high-level reports that ATF puts out. So we have no idea if the guns used in crime were used by the person who purchased it or if it was diverted to someone else.” In the former case, laws such as waiting periods and stronger licensure requirements may prevent people who commit crimes from being able to purchase guns; in the latter, more organized anti-trafficking efforts may be needed to dissuade gun buyers from funneling weapons into secondary marketplaces.

But Crifasi and other researchers believe that the ATF could still provide better data, such as the average time-to-crime numbers by crime type. However, the ATF has so far declined to share those numbers, including in response to a formal Freedom of Information Act request. “Honestly, I think they could release more,” says Daniel Webster, the director of the Johns Hopkins Center for Gun Violence Prevention and Policy. “But I think institutionally they just want to … limit everything,” he added, noting that the ATF is hamstrung by a lack of resources and pressure from gun-rights-focused lobbyists and members of Congress.

Right now, we know that gun sales rose dramatically starting in March 2020, and that murder—driven by gun murders—increased substantially a few months later. We have strong evidence that more people were carrying guns before murder went up in 2020, and the ATF data tell us that newly purchased firearms were used in more crimes than usual. It stands to reason that new guns helped feed 2020’s murder surge, though the data to confirm this conclusion remain agonizingly out of reach. The data aren’t perfect, but they’re strongly suggestive: More guns are behind America’s murder spike.

This article was originally published in The Atlantic. Sign up for its newsletter.