Since then, the murder of children in their classrooms has come to seem common, a regular feature of modern American life, and our fears so strong that we are certain the next horror is sure to come not long after the last.

The Education Department reports that  roughly 50 million children attend public schools for roughly 180 days per year. Since Columbine, approximately 200 public school students have been shot to death while school was in session, including the recent slaughter at Marjory Stoneman Douglas High School in Parkland, Fla. (and a shooting in Birmingham, Ala., on Wednesday that police called accidental that left one student dead). That means the statistical likelihood of any given public school student being killed by a gun, in school, on any given day since 1999 was roughly 1 in 614,000,000. And since the 1990s, shootings at schools have been getting less common.

The chance of a child being shot and killed in a public school is extraordinarily low. Not zero — no risk is. But it's far lower than many people assume, especially in the glare of heart-wrenching news coverage after an event like Parkland. And it's far lower than almost any other mortality risk a kid faces, including traveling to and from school, catching a potentially deadly diseasewhile in school or suffering a life-threatening injury playing interscholastic sports.