Louis Klarevas, a research professor at Teachers College at Columbia University, studied high-fatality mass shootings (six or more people) for his 2016 book “
Rampage Nation.” 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. But after the ban lapsed in 2004, the numbers in the next 10-year period rose sharply — a 183 percent increase in mass shootings and a 239 percent increase in deaths.
In a more recent
study co-written by him and published by the American Journal of Public Health in 2019, Klarevas also measured the impact of banning large-capacity magazines and concluded that such bans end up saving lives. “When LCMs were involved, the average death toll for gun massacres increased by 62 percent,” he said. “Jurisdictions that did not have LCM bans in place experienced a 129 percent increase in the incidence rate and a 206 percent increase in the fatality rate of gun massacres.”