Phone bans work, just not overnight, says the biggest study yet

About two-thirds of U.S. states now limit phones in school. So do they work? The largest U.S. study so far says yes, eventually.

Researchers from Stanford, Duke, the University of Michigan and the University of Pennsylvania compared more than 43,000 middle and high schools over three years, focusing on strict "pouch" policies where phones are locked away all day. The study, published through the National Bureau of Economic Research, found pouches really did cut phone use.

The first year was bumpy. Discipline incidents went up and student well-being went down. By year three, discipline was back to where it had been and well-being was higher than before the phones went away. Test scores barely moved on average.

Stanford's Thomas Dee put it plainly: "building effective, phone-free learning environments does not appear to be a simple or quick fix."

Why it matters for schools: if your school is in year one of a phone policy, a rough start is normal. Keep families in the loop with clear, regular updates so they see the long game.

Source: Stanford School of Humanities and Sciences, May 4, 2026