Large-scale study on gun-policy effects finds gaps in existing research, with a few exceptions

outcomes. In many cases, researchers found no studies linking gun policies to the many effects they examined.

“While science can teach us a lot about gun policy, research in this area is generally far behind where it is for most other causes of death that claim similar numbers of lives in the United States each year,” Morral said. “This does not mean that gun polices have no effects. Most laws probably have some effect, however small or intended. Instead, the limited evidence base reflects shortcomings in the contributions that scientific study has made to the policy debate.”

Many of the studies RAND reviewed used weak methods of establishing the effects of gun laws, often because historical information on variations in state gun laws is unavailable or difficult to collect. To encourage more high-quality research, the Gun Policy in America project created a large database of state-level U.S. gun policy laws, covering the period of 1979 to 2016. RAND is making this data set available to researchers and the public, and is using it to develop new estimates of the effects of gun laws that will be released later this year.

Because there is so little scientific evidence to draw on, RAND researchers also surveyed ninety-five gun policy experts from across the ideological spectrum to identify where there might be consensus or opportunities for compromise. Two groups with opposing views were identified among the experts. One group had views closely aligned with the National Rifle Association, and the other had views aligned with the Brady Campaign to Prevent Gun Violence.

Despite sharp disagreements on their ratings of the overall merits of different gun laws, the two groups of experts were often not far apart in their estimates of the likely effects of laws.

There was comparatively strong agreement between the groups of experts about the positive effects of expanded mental health-related prohibitions, the required reporting of lost or stolen firearms, media campaigns to prevent children from accessing guns, and the required surrender of firearms by those prohibited from possessing guns, such as people convicted of felonies.

The largest disagreements in opinion involved policies that allow the carrying of concealed weapons without permits and the elimination of gun-free zones. The