Even as Friday's shooting at Sandy Hook Elementary in Newtown, Conn., suggests that more could be done, the whole culture of school security has undergone a revolution since the 1999 Columbine school shooting, experts say.
"Schools are far more secure than they were at the time of Columbine," says Paul Timm, president of RETA Security Inc., a school security consultancy.
For one, he says, "They keep most exterior doors secured, which is something they didn't pay much attention to before."