Zero-tolerance measures can counteract what some experts consider a crucial tool for protecting students and the larger community.

After a former student killed six people last year at the private Covenant School in Nashville, Tennessee, state leaders have been looking for ways to make schools safer. Their focus so far has been to ramp up penalties against current students who make mass threats against schools.

Months after the killings, legislators passed a law requiring students who make such threats to be expelled for a year (unless a school superintendent decides otherwise) and allowing schools not to enroll them afterward. This year, the legislature passed bills that make the offense a felony and that revoke driving privileges for a year.

But a large body of research shows these zero-tolerance measures are not the most effective way to prevent violence in schools. In fact, some experts say those measures can counteract what they consider a crucial tool for protecting students as well as the larger community: threat assessments. When carried out correctly, threat assessments sort out behavior intended to cause real physical harm from simply disruptive acts and provide troubled students with the help they need.