But when we look at annual rates derived from the more complete dataset above, we see that only two of the 11 highest rates have occurred within the last eight years. Instead, six of the 11 highest rates were observed during the eight-year period between 1988 and 1995. 

The claims about the recent increase in mass public shootings are valid as long as we restrict our focus to the 1996-2013 period. As rates of crime and violence began to fall in the latter half of the ‘90s, so, too, did those for mass public shootings. Compared to the 1996-2006 period, there has been an uptick since 2007.

But within the broader context of the 32-year period, the annual rates since 2007 have been mostly typical. The average rate per 100 million over the 1982-2013 period was 1.31. Since 2006, two years (2008 and 2012) had above-average rates, four years (2007 and 2009-2011) had rates that hovered around the average, and two years (2006 and 2013) had below-average rates. Given that the average annual rate from 2007-2013 (1.51) is nearly the same as it was for the 1982-1995 period (1.50), we’ve recently returned to incidence levels commonly observed during the 1980s and early 1990s.