Following the ongoing outrage over the latest school massacre at Marjory Stoneman Douglas High School in Broward County, Florida, Congress and state legislatures are struggling to come up with an effective response. As various proposals are floated, a key question remains unclear: What type of gun-control legislation could actually make a difference?
Well, research published just last year suggests small-scale changes in the laws—derided by gun-control advocates as "nibbling around the edges"—would probably be pointless. The only effective answer is outlawing assault weapons.
"Assault weapons bans reduced the number of school shooting victims by 54.4 percent," Mark Gius of Quinnipiac University writes in the journal Applied Economics Letters. "All other gun-control laws—concealed-carry laws, private-sale background checks, and federal dealer background checks—had no statistically significant effect on school shootings."
Gius has received positive attention from conservative media for previous studies finding concealed-carry laws and assault weapons bans do not have a significant effect on a state's gun-related murder rate. (In many states, handguns are responsible for far more deaths than assault rifles.)
But his subsequent research shows mass shootings are a different matter.
In a 2014 study that analyzed data covering the years 1982 to 2011, he found "both state and federal assault weapon bans have statistically significant and negative effects on mass shooting fatalities."
In addition, he found the federal ban, which was in place from 1994 to 2004, was linked to fewer injuries from mass shootings. State-level bans were not, which suggests they are less effective in preventing harm (not surprisingly, since determined shooters can easily bring such weapons across state lines).
Gius' 2017 study focused exclusively on school shootings. Focusing on the years 1990 to 2014, he examined the effect of the federal assault weapons ban, federal background checks for gun purchases from dealers (in effect from 1994), and three types of state-level laws: assault weapons bans, "concealed carry" laws, and background checks for gun sales made by one individual to another individual.
"The only gun control measure that had a statistically significant effect on the number of school shooting victims was the assault weapons ban," he writes. "When the assault weapons ban, state or federal, was in effect, the number of school shooting victims was 54.4 percent less than (when it was not in effect)."
Gius adds two cautionary notes to these findings. First, such laws are one of many factors influencing school-shooting deaths.
"States that had above-average unemployment and gun ownership rates, along with greater than average alcohol consumption and larger student-age populations, had greater number of school shooting victims," he writes.
Second, while "school shootings are among the most horrific of crimes," they constitute "a very small share of overall murders." He estimate that the average reduction in such fatalities produced by a federal assault weapons ban "may be less than 10 per year."
So if our goal as a society is to reduce the overall murder rate, an assault weapons ban would be highly ineffective. But if we want increased protection from people who aim to create mass casualties in schools—or concert venues like the one in Las Vegas—it could be of enormous help.