In schools across America, students are practicing what to do in case there’s ever a school shooting.

Active shooter drills are becoming a regular part of the school year in some places. In fact, a growing number of states now require them.

On one hand, the drills can help make sure students and teachers know how to respond if there’s ever a school shooting. Students can learn where to go to stay safe or the safest evacuation routes. Drills can also help prevent someone from freezing in a moment of crisis.

On the other hand, some advocates say active shooter drills can be scary and cause trauma that leads to issues, either immediately or in the future.

Some research presents evidence these drills can be especially tough for people with anxiety or developmental disorders. What some researchers say is missing is studies that say these drills help save lives. Those researchers say there isn’t enough school shooting data to get reliable results.

A Secret Service researcher says the approach is wrong. She was lead author on a recent report that emphasized threat assessment and prevention.

The report says bullying and ostracism are two of the top sources of student distress. The report also suggested school take an “all in” approach to addressing those issues and others. That means involving everyone from teachers to administrators to mental health professionals.

And while holding drills can provide peace of mind, the Secret Service says social and emotional interventions are most effective in the long term.