The students praised the shooting practice at Oxford High. But do they really work?

For example, some students armed themselves with objects like scissors, which could make an assailant more likely to shoot, he said. Mr. Guilbault said the ALICE training does not encourage students to arm themselves with specific tools, but discusses the use of nearby objects to “create a distraction.”

The barricade also has detractors. Teachers in Oxford used a product called Nightlock, a barrier at the bottom of doors, and some students said they blocked them with furniture. But evidence from past school shootings suggests barricades may increase noise and tell gunmen where people are hiding, Mr Dorn said.

The most important strategies for students and teachers to use when an active shooter is to lock doors, turn off lights, hide out of sight, and ignore knocks on the door or questions. from outside a room, said Jaclyn Schildkraut, a professor of criminal justice at the State University of New York at Oswego, who studies school lockdown drills.

But the biggest questions about active marksmanship go beyond tactics – and reverberate through how schools should balance the threat of violence with the mental health of students.

Dr. Schildkraut’s research suggested that even relatively gentle locking exercise can “slightly” decrease students’ sense of safety in school, she said. But she argued that the exercises were necessary because the teens who participated in them reported “feeling more prepared and more independent,” she said. “It’s better to have it and not need it than to need it and not have it.”

Experts agree that the younger the students, the more carefully the exercises should be conducted, with an emphasis on overall safety and listening to adults in unusual circumstances, instead of the specific threat of gun violence.

But almost all American children will eventually come across the existence of school shootings.

In Chicago, Sara Rezvi, a former public school teacher who now runs an after-school program, recalled a ninth grade girl asking her during a lockdown exercise, “Ms. Rezvi, take it. would you shoot us if someone came in with a gun? “

Maria D. Ervin