COLUMBUS, Ohio (AP) - Police, school employees, security consultants and others say threats to schools are increasing nationwide.
They come both from local students and outsiders seeking to cause disruptions or a big emergency response.
One researcher estimates there were about eight bomb threats per school day nationwide during the 2015-16 school year, and that doesn't include other threats of violence or disruption.
Ohio is believed to be among the states with the most threats. The Associated Press tallied more than 170 there in the 2015-16 school year.
Learning time lost to evacuations and cancellations adds up, as do the hours police spend responding and investigating.
Less measurable are the ways threats can dent staff and students' sense of security even when they're false alarms, as they almost always are.
Administrators and law enforcement responding to school threats must quickly evaluate them to determine how to respond. Some factors they consider:
TYPE AND DETAIL
Is the threat of a bombing, a shooting, or other specified or unspecified violence? It is vague or presented with details, such as an exact target, time or location? Responses can vary significantly depending on this information. A vague threat at a multi-school campus might lead to evacuations or lockdowns affecting many more people than a threat against someone specific in a particular class.
Schools receive threats via phone calls and messages, paper notes, messages written on school property, emails, social media and other forms. Sometimes the method of delivery helps officials determine who's responsible for the threat and whether real harm might be imminent because they can, for example, trace a Facebook post to a particular account or assess whether a call came from out of state.
MOTIVE AND CAPABILITY
Learning the responsible party's motive, such as getting a class canceled or hurting someone who has wronged them, and information about whether the person would actually have the means and ability to follow through on a threat also can help determine its legitimacy.
How a school has planned for or practiced various responses, such as lockdowns and evacuations, can also factor into whether such orchestrated options are used in threatening or emergency situations.