Who are school shooters? A Safe School Initiative study reported that out of 37 incidents, all of the perpetrators were male, ranging in ages 11 to 21. Three quarters of them were white and most were living with at least one biological parent. Over 40 percent were doing well in school, receiving As and Bs. While 34 percent felt themselves to be “loners,” 40 percent socialized with “mainstream” students. In addition, nearly two-thirds of the shooters had never been in trouble or rarely were in trouble. Over 70 percent felt bullied and 60 percent had been extremely depressed. Of course, these numbers fit not only the 41 kids who did murder their schoolmates, but also hundreds of thousands of America's 55 million K-12 students who will never shoot anybody. Reason Science Correspondent Ronald Bailey looks into research that tries to assess and abate the risks of school shootings.