Mass Public Shootings have tripled since 2011.

HICRC researchers Amy P. Cohen, Deborah Azrael and Matthew Miller reported in Mother Jones that the United States has entered a new period in which mass shootings in public places are occurring more frequently.   Using a Statistical Process Control method developed for industry when events are relatively rare, the HICRC researchers found that between 1982-2011, mass shootings occurred every 200 days on average; from 2011-2014, they have been occurring every 64 days.  Those claiming that the rate of mass shootings has not changed inappropriately include intimate partner homicides in private homes in their data http://m.motherjones.com/politics/2014/10/mass-shootings-increasing-harvard-research.  See also Deb Azrael interview On the Media October 31, 2014.