Yesterday afternoon, a gunman dressed in a black trench coat walked into a lecture hall on the campus of Northern Illinois University in DeKalb, Ill. He used a shotgun and two handguns and opened fire on the unsuspecting students. When it was over, at least seven persons were dead, and well more than a dozen were injured. It's the kind of story we report on much too often. [See NIU shootings news story.]

I spoke this morning with one of our regular experts on the topic of school security issues: Patrick Fiel, former head of security at D.C.'s public schools and now a safety advisor with ADT Security Services. Fiel was at the annual conference of the American Association of School Administrators, which is largely focused on K-12 schools, and he said that on the show floor, the shootings seemed almost to be a non-issue: "It was business as usual," said Fiel, "which is sad."

Fiel agreed that such incidents are accelerating in frequency, and that he foresees an increase in similar, future incidents. Fiel added that it's only the most dramatic incidents that get reported. "We don't hear [in national news] about the one- and two-victim incidents that are happening." He notes that there were 32 violent deaths in campus-related incidents last year -- and that was just the numbers for the K-12 schools, so it doesn't include incidents like the Virginia Tech murders.

So what do we do? And I think we'd all agree that measures have to be taken to prevent such incidents… Here's are 10 of the top elements that Fiel suggests: