There is a new report of violence in schools , this time in Pennsylvania. Several children are reported killed and wounded as authorities try to figure out what happened and why.

It was the same last week, too. Two tragedies in Bailey, Colo.,  and in Cazenovia, Wis.,  brought the school violence thing  back to front and center.

The violence that occurs at schools  is particularly terrifying because it involves our kids. No one wants young people exposed to violence and fear—protection is a primary element of parenthood. Plus, it always seems so random. Rural school in Arkansas, suburban school in Colorado, working-class school in Oregon, elementary school in Detroit. It seems impossible to predict, adding to the fearsome nature of the event. But there are clues to when and how these events develop, and who might be thinking of acting out the pattern. This study , while old, was prepared at the height of the "epidemic" of school violence in the 1990s. Its conclusion is simple: School shootings are not as prevalent as they seem. Schools are safer than home for the majority of kids.

At root, some kids start going in the direction of violent action, but they are not invisible. Neighbors, teachers and peers can note certain problem developments and help curtail taunting and divisions between student groups. At home, pressure to achieve might push a kid to desperation. As this report  suggests, though, parents and teachers tend to take preventive action early, rather than too late—erring on the side of caution. Then again, you have cultures of violent response  to perceived threats. Access to guns  is a prime cause of youth gun violence .