School threats have risen by 158%, according to a study released by the National School Safety and Security Services organization. Almost a third of those threats led to school evacuations, and about a third of those were disseminated on social media.
Faced with increased threats, the challenge for schools is to determine when to evacuate. There are no national guidelines for administrators on determining threat levels, and most decisions to close are made by superintendents and school boards, often in conjunction with police departments or emergency services.