Americans are killing one another less often, but when they do they go all out. Since 1980, the total U.S. homicide rate has fallen by more than half even as the rate of random mass shootings has increased, according to University of Alabama criminologist Dr. Adam Lankford. Based on data from a recent New York Police Department study of “active shooters”—those who attempted to murder people at random in crowded, confined areas—the rate of such shootings has gone up more than 11 times. 

Counting only random mass murders with at least two casualties, Lankford found that 179 such crimes occurred between 1966 and 2010, an average rate of 3.97 per year. From 1966 to 1980, there were 20 mass killings for a rate of 0.75 per year, but in the 1980s the rate doubled to 1.8 per year, tripled in the 1990s to 5.4, and went up 160% in the 2000s to 8.7 per year. The rate could easily reach 10 per year during the present decade. If one counts attempted mass murders, the rate is about 26 per year.

Over the course of those three decades, not coincidentally, the gun industry invented and began to mass market auto-loading, assault-style rifles like the AR-15, which is the civilian version of the Army’s M-16. The AR-15 has become the weapon of choice for mass killers in large part because the high capacity magazines available for it allow them to kill a lot of people very quickly. At present, there are at least 3.75 million AR-15 style rifles floating around the U.S., along with millions of other equally lethal types of “assault-style” rifles.

Yet mass killers use handguns, many of which are also able to accommodate high-capacity magazines, even more frequently. Looking closely at mass killings between 2006 and 2010, USA Today recently pointed that two-thirds of mass killers used a gun, and overwhelmingly used a handgun over any other sort of weapon.

-Matt Bewig

To Learn More:

Guns, Mental Illness and Newtown (by David Kopel, Wall Street Journal)

Mass Killings Occur in USA Once Every Two Weeks (by Meghan Hoyer and Brad Heath, USA Today)

Is the AR-15 becoming the Weapon of Choice for Deranged, Young Male Mass Murderers? (by Noel Brinkerhoff, AllGov)

Are Mass Shootings Becoming More Frequent—and More Deadly? (by Adam Lankford, Huffington Post)