They compared that to data on background checks, Google searches for "buy gun" as a proxy for gun sales and searches for "clean gun" to account for people taking their guns out of storage.
Gun sales in the United States can increase after mass shootings. Serious discussion of gun control laws leads to increased public interest in firearms, which apparently results in more people being shot and killed.
Accidental deaths related to firearms increased 27 percent in the months following Sandy Hook, including a 64 percent increase in gun-related deaths of children, said senior researcher Robin McKnight. But this is the first time researchers have found a coincident surge in accidental gun deaths: Levine and McKnight studied trends in firearms sales and accidental gun deaths from 2008 through 2015 and found no other instances of such a pattern.
That means there's no national database of gun purchases, so it's hard to tell how many guns are sold.
Levine said that he and McKnight made a decision to do the study after seeing data in an article in The New York Times that showed a dramatic surge in gun purchases after Sandy Hook and again after 14 people were gunned down on 2 December 2015 at a public health department Christmas party in San Bernardino, California.
"If you have an estimated 3 million more guns in homes, in all likelihood, not all of those guns will be safely stored and may be loaded and accessible, and that results in unintended harm". They have grappled with what conditions would best determine the factors - gun sales, different state laws, the type of guns available - that might affect gun violence and death. They suspect that people who bought guns or pulled them out of storage-presumably over fears of a government clampdown-are "unlikely to be motivated by an intention to kill themselves or others".
The findings were published December 8 in the journal Science. "That is really what allows them to make causal claims about firearm exposure and accidental gun deaths". That has held true even as the number of guns in circulation has grown enormously, from 0.36 per person in 1948 year to 1.13 in 2014, notes David Kopel, an adjunct constitutional law professor at the University of Denver Sturm College of Law. Because the authors are limited by the lack of reliable data on US gun ownership, she says, "they do something smart".
The event is part of a nationwide tribute in partnership with the Newtown Foundation, Newtown Action Alliance, Brady Campaign to Prevent Gun Violence, Everytown Survivor Network and Moms Demand Action for Gun Sense in America, Faiths United to Prevent Gun Violence, Organizing for Action, States United to Prevent Gun Violence, St Marks Episcopal Church, and Women's March.
But she is critical of at least one aspect of the study. Although it's also possible that it could have been people who were just curious.
The researchers wrote that their analysis "provides evidence indicating that the spike in gun exposure that followed the Sandy Hook school shooting increased the incidence of accidental firearm deaths". "It has to be about what's occurring that's leading them to not be stored properly at that moment". The policy was challenged in certain states, but data shows the states that did ban domestic abusers from gun ownership reduced gun murders by 17%.
One nagging question in the new study, Cook noted, is that while the spike in gun sales after Sandy Hook was significant, it only added a small amount of guns to the country's total gun stock.
That corresponded with an increase in Google searches for "buy gun" and "clean gun" during the same five-month window.
McKnight and Levine also looked at national- and state-level mortality data to see if the increase in gun searches and sales correlated to any accidental gun deaths. From it, they estimate that 3 million additional guns were sold in the months following the shooting. "It's not a flawless proxy", Levine says.
The findings run contrary to a recent decrease in accidental gun deaths, despite an overall increase in gun sales - but it's hard to draw conclusions from that trend, Poliquin says.