Thanks to a 1996 ban on federally funded firearms research in the US, there is an appalling lack of data surrounding gun violence.
A new study from Harvard researchers, however, examined past data and found that a simple gun policy could save hundreds of lives each year if it is implemented nationally.
When more than 33,000 Americans die each year from gun-related violence something clearly needs to change. But the next step will remain unclear if the US continues to inhibit research that examines what sort of legislation will be most effective.
Previous research from outside the US has suggested that a waiting-period between the sale and delivery of a gun can reduce suicide and anger-driven violence.
After the 2012 Sandy Hook Elementary School shooting, Harvard researchers were compelled to take a closer look at the effectiveness of mandatory waiting-periods. So the researchers began to track down past data on waiting-period laws.
"Instead of saying, 'Isn't it a tragedy, children are dying, oh well, on to the next meeting,' we decided we wanted to do something," says Deepak Malhotra, a negotiation and conflict resolution researcher who co-authored the new study with economist Michael Luca.
The researchers specifically compared shooting-related homicides and suicides in states that implemented a 2-7 day waiting period for handguns.
The results revealed that no matter the length of the mandatory waiting-period, states that employed such restrictions had on average 17 percent fewer murders and 10 percent fewer suicides.
With this information, the researchers had to figure out whether the correlation meant that the waiting-periods were directly responsible for the reduction in gun-related deaths. They desperately needed a real-world situation that they could analyze.
The researchers struck gold when they discovered that in 1994, when the Brady Handgun Violence Prevention Act was passed, 19 states were forced to implement a 5-day waiting-period in order to carry out compulsory background checks. By examining these 19 states in particular, researchers found a 17 percent decrease in gun-related homicides and a 6 percent reduction in suicides when waiting-periods were implemented.
Then in 1998, thanks to advances in computing, the speed of these background checks was improved so dramatically that a waiting-period was no longer necessary. Some states responded to the improved technology by getting rid of the waiting-period, while other states kept it as law.
Currently, there are 17 states with waiting-period laws. By comparing the states that removed waiting-periods to the states that retained them, the researchers estimated that about 750 gun-related homicides are avoided every year from mandatory waiting-periods.
Furthermore, the researchers predicted that if all fifty states implemented these waiting-periods, an additional 910 lives could be saved each year.
"Absolutely, this study demonstrates a robust association between waiting periods and gun deaths," says Margaret Formica, a public health researcher at the State University of New York Upstate Medical University in Syracuse who studies firearms deaths but wasn't involved in the new work.
But Formica warns the study is limited because it cannot examine outcomes for individual gun purchasers.
"You can't tell if gun purchasers were the ones directly affected, so you can't know for sure that it's a causal relationship," she said.
The American Association for the Advancement of Science (AAAS) argues that until Congress removes the restrictions on funding for federal firearm research, researchers cannot confirm whether or not these relationships are causal.
"Decades ago, we did not know infant car seats should be rear-facing," their letter to Congress notes.
"Robust research on car accidents and subsequent legislation has helped save hundreds of thousands of lives without preventing people from being able to drive. It's time to apply the same approach to reducing gun violence in our communities."
The study was published in Proceedings of the National Academy of Sciences.