Passing an assault weapons ban might prevent 170 mass shooting deaths a year in the US, experts who support gun control estimate. Passing a universal background check law could prevent 1,100 gun homicides each year. Raising the age limit for buying firearms could prevent 1,600 homicides and suicides.



These are some of the new estimates in a groundbreaking study of the potential impact of American gun control laws. The non-partisan analysis, based on a review of existing gun policy research and a survey of the best guesses of both gun rights and gun control experts, was conducted by the Rand Corporation, which spent two years and more than $1m on the project.

Photograph: Rand Corporation

Rand’s review of the existing research concluded that only a handful of gun control laws were backed by strong research evidence. Child access prevention laws, which are designed to keep guns out of the hands of children, had the strongest evidence behind them, the researchers concluded, and appeared to reduce gun injuries and suicides. The review also found “moderate evidence” that background checks reduce firearm suicides and homicides, and that certain mental health gun prohibitions reduced violent crime.

The Rand review also found “moderate evidence” that “stand your ground” laws, which allow Americans to use guns to defend themselves without first attempting to retreat from a confrontation, may increase state homicide rates.

What the two-year project revealed most starkly were the gaping holes in both the research and the basic data needed to understand what gun laws might save the most lives.

Photograph: Rand Corporation

There was only “inconclusive” research evidence about the impact of a ban on assault weapons and high-capacity magazines on mass shootings and on violent crime. There was no rigorous research of any kind about the impact of gun-free zones. The research on the impact of laws making it easier to carry concealed firearms was “limited” or inconclusive”.

That lack of evidence is not an accident, but a political choice, shaped by more than two decades of opposition to federally funded gun research from the National Rifle Association (NRA) and other gun rights advocates.



Having no research to answer crucial gun debate questions “creates a fact-free environment, where people can make claims that make problems for legislation moving forward”, Andrew Morral, the lead researcher on the project, said.

Photograph: Rand Corporation

Congressional Republicans passed the 1996 Dickey amendment to pressure the Centers for Disease Control and Prevention (CDC) away from conducting public health research on gun violence. The political pressures have never amounted to a total ban on federal funding for gun-related research. The justice department, for instance, has continued to fund important studies in this area, often focused on policing and community strategies for preventing shootings. But the amount of money the US government spends on research to prevent gun deaths is a fraction of the amount it spends on comparably prevalent causes of death and injury.



To fill in those gaping holes in what Americans know about how different gun control laws might work, Rand did what policymakers might do when there is no study offering a simple answer: they surveyed longtime gun policy experts about their best guesses about the impact of different laws.

The experts, who included gun policy researchers and affiliates of advocacy groups such as Everytown for Gun Safety, the National Rifle Association and the National Shooting Sports Foundation, provided their best guesses about how much a given law might affect gun homicides, gun suicides, gun accidents and mass shooting deaths, as well as how much each policy might affect gun industry sales.

Photograph: Rand Corporation

Rand sorted out experts by their self-described affinity to gun rights or gun control groups, and these two groups of experts often provided opposite estimates of what impact the policies might have. Gun rights advocates guessed than a ban on assault weapons and high-capacity magazines might lead to a 1% increase in gun homicides, or 100 more lives lost.

Unlike most in-depth research studies, Rand’s project is designed to be accessible to the public. It includes a website that allows users to explore the potential human impact of passing individual gun laws, or packages of potential gun law compromises.