Just read an article on a Crime Prevention Research Center study in which they analyzed nearly 20 years of comprehensive data from reliable, respected sources including the National School Safety Centers (NSSC) report, “School Associated Violent Deaths” and the Washington Post’s database of school shootings. The report indicates that as far back as January 2000, there has not been a single mass public shooting between 6 AM and midnight in any school that allows teachers and staff to carry guns legally. Here is a
link to the abstract. There are links to the paper and the data on the abstract webpage.