What does the latest academic research on the effectiveness of gun laws to prevent mass shootings show?
The short answer is that many proposed laws probably would not have much impact on curbing the mass shootings that dominate the news, reports the Washington Post fact checker. Still, the laws could help lessen their severity, and might also bring down overall gun violence. Mass shootings do not happen often enough for detailed data analysis. By some definitions, a mass public shooting is any event in which four or more individuals, not including the assailant(s), were killed by gunfire in a public setting within a 24-hour period. Under this definition, there were three or four mass shootings a year through most of the 2010s, but then the number spiked to seven in 2017, 10 in 2018 and eight in 2019.
Criminologist James Alan Fox of Northeastern University said most mass shooters are very determined individuals and that even with an average of seven or eight mass shootings a year, new laws might reduce the number by only one a year. He said stricter gun control laws would be “the right thing to do for a different reason” — they might help reduce overall gun violence. While states with tougher gun laws tend to have lower gun fatality rates, those rankings change when suicides — which make up about 60 percent of gun deaths — are excluded. In 1994, President Bill Clinton signed into law a ban on assault weapons and large-capacity magazines. The law — which grandfathered in an estimated 1.5 million assault weapons and 25 million large-capacity already owned by Americans — was in place for 10 years until Congress let it lapse. Some research suggests the ban became more effective toward the end of the 10-year period because it helped cap and then reduce the supply of assault weapons and LCMs. Louis Klarevas, a research professor at Teachers College at Columbia University, studied high-fatality mass shootings. He said that compared with the 10-year period before the ban, the number of gun massacres during the ban period fell by 37 percent and that the number of people dying because of mass shootings fell by 43 percent. After the ban lapsed in 2004, the numbers in the next 10-year period rose sharply — a 183 percent rise in mass shootings and a 239 percent rise in deaths.