A paper on mass public shootings by Adam Lankford (2016) has received massive national and international media attention, getting coverage in the New York Times, the Wall Street Journal, plus hundreds of other news outlets spanning at least 35 different countries. Lankford’s claim was that over the 47 years from 1966 to 2012, an enormous amount of the world’s mass public shooters — 31% — occurred in the United States. Lankford attributed this to America’s gun ownership.
Lankford’s study reported that from 1966 to 2012, there were 90 public mass shooters in the United States and 202 in the rest of world. We find that Lankford’s data represent a gross undercount of foreign attacks. Our list contains 1,448 attacks and at least 3,081 shooters outside the United States over just the last 15 years of the period that Lankford examined. We find at least fifteen times more mass public shooters than Lankford in less than a third the number of years.
Given the massive U.S. and international media attention Lankford’s work has received, and given the considerable impact his research has had on the debate, it is critical that this issue be resolved. His unwillingness to provide even the most basic information to other researchers raises real concerns about Lankford’s motives.
Here is a graph that the New York Times put together using Lankford’s data (data on the rate of mass public shooters by country that has not been released to anyone other than the New York Times) and our graph using the corrected data. While the graph with Lankford’s data shows a positive relationship between the rate of mass public shooters and Small Arms Survey measure of gun ownership (it appears to be driven by the outliers of Yemen and the US), our graph implies a slightly negative relationship. Click on Figures to enlarge.
“Because of faulty research, it is widely believed that a disproportionate share – 31% – of the world’s mass public shooters occurred in the United States,” said Professor Paul Rubin, Samuel Candler Dobbs Professor of Economics, Emory University. “In fact, John Lott’s careful analysis of a very large data set – 437 – pages – shows that the proper number is about 2%, less than the U.S. share of world population. One can only hope that this important research will correct the record.”