Via Mother Jones – By Amy P. Cohen, Deborah Azrael, and Matthew Miller

“Editor’s note: The authors are scholars from the Harvard School of Public Health and Northeastern University; this article details their independent research, which is based on the mass shootings data Mother Jones has collected and published since 2012. In June, following gun attacks in California and Oregon, President Obama remarked that mass shootings are “becoming the norm.” But some commentators claim that mass shootings are not on the rise. So which is it? Have mass shootings become more common? According to our statistical analysis of more than three decades of data, in 2011 the United States entered a new period in which mass shootings are occurring more frequently. Our analysis used data compiled by Mother Jones on attacks that took place in public, in which the shooter and the victims generally were unrelated and unknown to each other, and in which the shooter murdered four or more people. (An incident with four or more homicide victims was the threshold count for mass killing established by the FBI a decade ago; a federal law signed by President Obama in 2013 defined the threshold as three or more victims killed.)”