In his State of the Union address, President Biden said that mass shootings tripled after the federal ban on assault weapons expired in 2004. That claim is the subject of dispute, says the Washington Post fact-checker. In 1994, President Clinton signed a ban on assault weapons and large-capacity magazines (LCMs), defined as those that could hold more than 10 rounds. The law — which grandfathered in an estimated 1.5 million assault weapons and 25 million LCMs already owned — was in place for 10 years until Congress let it lapse. Biden He appears to rely on a study of mass shooting data from 1981 to 2017 published in the Journal of Trauma and Acute Care Surgery by a team at New York University’s Langone Medical Center. That group found that an assault weapons ban would have prevented 314 out of 448, or 70 percent, of the mass shooting deaths during the years when the ban was not in effect. The data have come under attack by some analysts.
Prof. Louis Klarevas of Teachers College at Columbia University studied high-fatality mass shootings (involving 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 in 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 increase in mass shootings and a 239 percent increase in deaths. c
Correlation does not necessarily equal causation. James Alan Fox of Northeastern University, in a 2016 study with Emma Fridel, noted that “rather than assault weapons, semiautomatic handguns are the weapons of choice for most mass shooters.” About 70 percent of mass public shootings after 1992 relied exclusively or primarily on semiautomatic handguns. They wrote that “the frequency of incidents was virtually unchanged during the decade when the ban was in effect” and that “not only were there countless assault weapons already on the street, but also assailants had a variety of other powerful firearms at their disposal.”