TL;DR
PISA results keep sliding across countries, and the evidence from school phone bans suggests they help high-schoolers, slowly and in more ways than test scores alone.
PISA tests 15-year-olds worldwide every three years, and the 2025 results are the worst on record for OECD countries. Maths, reading and science all fell. COVID closures cannot explain the whole story: in many countries scores started dropping years earlier, and after the pandemic years they did not rebound — they did not even slow down.
The timing lines up with phones
The decline began around the mid-2010s, exactly when smartphones became ubiquitous among teenagers, schools adopted one laptop per child, and short-form video took over social media. The authors of the PISA report say so themselves: students read less for pleasure and have shifted to skim-reading feeds, which may be eroding their ability to handle long texts. And a device engineered to capture attention looks a poor match for sustained academic focus.
That leaves a narrower, answerable question: what happens when schools take the phones away? More than twenty US states and dozens of countries have done it, handing researchers a batch of natural experiments.
The headlines told half the story
A team at NYU Stern rounded up seven of these experiments. One study got most of the coverage, with the finding that bans have 'close to zero impact' on scores — but that number pools middle and high school together. High-schoolers used their phones two to three times as much; in high schools the ban did cut use, and maths scores rose a little, worth about one to two extra months of school. The problem is that the sample contained three times as many middle schools, which diluted the high-school effect.
Two other studies from the same period went largely unnoticed. In Norway, after a ban, fewer girls sought care for psychological symptoms, fewer reported being bullied, their grades improved and more went on to an academic track — with the biggest gains for girls from low-income families. In Rio de Janeiro, banning phones during class alone did almost nothing; only a full school-wide ban produced real gains in maths and Portuguese.
Look past the test scores
What schools actually wanted to change was the school day: less distraction, more face-to-face talk, less bullying, classrooms a teacher can manage. Two studies found disciplinary incidents rose in the first year, then fell back to baseline or lower by year two or three — an adjustment period, not a failed policy.
Future research should measure noise, playground activity, conversations, library checkouts and teacher burnout. And every study must first confirm that phone use actually dropped: if a policy is so poorly enforced that students keep scrolling, nothing else will improve.
In one line: phones are not the only reason scores are falling, but taking them out of the classroom is one of the few moves with visible results.
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