Interesting conclusions from a new gun study: Imposing a waiting period between the initiation of a gun purchase and the close of the sale significantly reduces deaths by gun violence. The study, which appears in the Proceedings of the National Academy of Sciences, shows that in the 17 states (including the District of Columbia) that have waiting periods of three to 14 days, gun homicides are reduced by approximately 17%, or 750 deaths per year.


Three Harvard Business School professors tracked policy changes from 1970 to 2014, as well as a subset of gun-violence data: the effect of the federal law that imposed a waiting period in some states on gun purchases from 1994-1998. They found that even short waiting periods “cause large and statistically significant reductions in homicides”; waiting periods also reduce suicides, though the effect is not quite as large.


Why gun deaths drop with waiting periods is not exactly clear, but it appears to be due to a “cooling-off” period—if you’re pissed at your neighbor but are forced to wait a week before you can actually point a gun at him, you might chill out in the meantime. “Visceral factors, such as anger or suicidal impulses, can spur people to inflict harm on others or themselves, but tend to be transitory states,” note the authors.

The researchers conclude that expanding the waiting period to all 50 states would save an additional 910 lives a year. The authors note that the majority of Americans support waiting periods, and that legislation enforcing this cooling-off period “would therefore reduce gun violence without imposing any restrictions on who can own a gun.”