Phyllis Deal, a paraprofessional at J.W. Riley Elementary in Milwaukee, explains her school's system. Go into lockdown mode. That way substitutes or other legitimate outsiders in the building will get the message. Villahermosa reserves codes for hand signs among staff. A closed fist means the stranger has a weapon.
Teachers can carry yellow and red cards to the playground.
If there's a problem, send a child with the yellow card to the office. The red card signals an emergency. Look at new resources for defusing student violence. Several states have established university-affiliated centers for school safety as clearinghouses. The Center for the Prevention of School Violence at North Carolina State University provides information on programs like School Resource Officers.