An FBI report released on September 16th, 2014 makes the assertion that active shooter attacks and deaths have increased dramatically since 2000 – both increasing at an annual rate of about 16 percent. As the headline in the Wall Street Journal stated: “Mass Shootings on the Rise, FBI says.”
But the FBI made a number of subtle and misleading decisions as well as outright errors. Once these biases and mistakes are fixed, the annual growth rate in homicides is cut in half. When a longer period of time is examined (1977 through the first half of 2014), deaths from Mass Public Shootings show only a slight, statistically insignificant, increase – an annual increase of less than one percent.
The FBI’s misleadingly includes cases that aren’t mass shootings – cases where no one or only one person was killed in a public place. While the FBI assures people that it “captured the vast majority of incidents falling within the search criteria,” their report missed 20 shootings where at least two people were killed in a public place. Most of these missing cases took place early on, biasing their results towards showing an increase.
The paper can be downloaded here.