Do Phone Bans in Schools Make a Real Difference?

Adolescents today are more digitally connected than ever before. 

Most teenagers in the U.S. have a smartphone, and nearly half told the Pew Research Center in 2024 that they’re online "almost constantly," browsing social media platforms that are designed to capture and hold their attention.

But the impact of phones on kids is still debated. On one hand, this widespread connectivity has been linked to rising rates of depression and anxiety in youth; in schools, teachers have also reported that smartphones can be highly disruptive to learning. On the other hand, smartphones enable kids to do plenty of crucial things in their daily life: connect with friends or parents, access school materials, listen to music, hop on a bus, buy a snack, or look something up in the moment.

Stanford economist Matthew Gentzkow, the Landau Professor of Technology and the Economy in the School of Humanities and Sciences and Faculty Director of Stanford Impact Labs, has had a front seat to this debate, as part of his research on phones and kids. 

“The question I wrestle with isn’t whether phones are bad or good,” he says. “The question I’m motivated to answer is: In a world where attention-grabbing cell phones are ever-present, and very capable of offering kids access to both good and bad influences, what measures work to help kids learn, grow, and thrive?” Gentzkow’s research stretches across contexts—looking at what works to support youth well-being in both home and school environments.

In recent years, one approach being aggressively tested is policies that either restrict phones during class or ban phone use outright at school. Nearly all school districts in the U.S. are now experimenting with new policies, and parents, educators, state lawmakers, and researchers alike are eager to see what results will emerge. 

With support from Stanford Impact Labs, Gentzkow teamed up with psychologist Angela Duckworth, the Rosa Lee and Egbert Chang Professor at the University of Pennsylvania, and a group of researchers working across Stanford, Penn, Duke University, and the University of Michigan, to generate evidence on how school phone policies affect student outcomes. 

“A key thing that has been missing from the conversation about phones and kids is clear data on school cell phone policies. Through the amazing efforts of our interdisciplinary team, we were able to assemble the first comprehensive national data set on these policies and use them to provide credible estimates of the impacts of phone policies,” says Gentzkow.

Finding a baseline

Against a backdrop of varying restrictions and bans, Gentzkow, Duckworth, and team chose to collect phone use data from a variety of schools. They opted to focus their initial study specifically on schools where lockable pouches were deployed to separate students from their devices. By comparing schools with an unambiguous intervention to those without one, the research could take clear shape. 

The schools in the study purchased and distributed magnetically sealed pouches made by Yondr, a San Francisco-based company, to their students. (As of early 2026, a reported three million students across U.S. schools were using Yondr pouches.) These schools also followed a similar daily protocol: When students arrived each morning, their phones would be placed in pouches, and they generally would not be able to access them until the end of the day. 

Deciding what indicators to measure became a collaborative effort. Early conversations with educators gave the researchers a better grasp of what most worries teachers about phones at school, and those concerns shaped both the survey structure and the outcomes the team tracked: phone usage, test scores, attendance, student well-being, and even online bullying.

Duckworth calls the team’s close work with teachers and administrators from the very beginning one of the project’s “great triumphs.” Teachers shared their classroom observations, their views on whether school phone policies should be stricter, and which outcomes mattered most to them. “We learned that teachers want their students to pay attention in class, learn, and do well academically. But they would also like students to develop social skills and connection,” says Duckworth. 

After surveying over 4,600 schools using Yondr pouches, the team found that overall phone use among students trended lower and reported well-being trended higher, while many other indicators did not change considerably. Banning phones during the school day did not improve standardized test scores over a three-year period, and there was little evidence that policies affected school attendance, classroom attentiveness, or online bullying. Math scores among high school students (but not middle schoolers) increased, albeit modestly.

Students themselves were not surveyed by the research team as part of the study, but Duckworth and Gentzkow say they would like to include students in future studies.

Behind the scenes of a nationwide school study

Establishing how best to capture and measure the effects of phone bans was no small task, Duckworth and Gentzkow emphasize. 

Yondr provided the team with data on when pouches were being used, so researchers would have accurate data on the adoption of phone restrictions. Individual states provided data on standardized test scores, attendance, and disciplinary outcomes. The researchers also collected data from the technology platform Panorama Education, which surveyed students’ subjective well-being, classroom attention, and reports of online bullying. 

Through Duckworth’s longstanding work in schools, the team was also able to disseminate a national survey to teachers through partnerships with state education leaders and direct outreach to educators. The information gathered in the survey has bolstered the team’s data collection efforts across a wide range of schools with varied restrictions and bans. Since the survey was released in 2025, nearly 108,000 educators from all 50 states have responded. Teachers reported on when phones were restricted during the day (whether it be the entire day, or just during classes), where the phones were kept (stowed away in a locker, on the student, or collected by staff), how consistently their school’s policy was being enforced, and their overall level of satisfaction with the policy. 

“Field research is difficult because it requires an organizational partner,” says Duckworth. “When you’re trying to capture what is going on in the totality of the 50 states, that is even more difficult.” In this case, shared concern around the issue went a long way to shoring up the team’s partnerships. “We built partnerships mostly by telling people what we were out to measure”, she notes. “We went to the National Education Association and the American Federation of Teachers, and they said ‘We support this.’ We also went in parallel to the two major charter school organizations: the National Alliance for Public Charter Schools and the Charter School Growth Fund.” 

The research effort was funded in large part by the National Governors Association (NGA), which represents all 50 states. “After securing that support, we went one by one to every state and asked: 'Would you have half an hour to learn about this project? Can we count you in?',” says Duckworth. Ultimately, 37 state partners—including administrators and teachers unions—helped the research team disseminate the survey using newsletters and social media. The NGA helped connect them with state leaders. The overall reach, Duckworth says, “is a great demonstration of the sort of work Stanford Impact Labs can make possible.”

“We describe this project as a moonshot," Duckworth adds, "because it brings the educator perspective into a policy debate, and educators are the ones best positioned to tell us what’s happening in their schools.”

The path ahead

Moving forward, the research team hopes to shift their focus to building a clear understanding of what it takes to keep students engaged in school. Perhaps, Duckworth suggests, the answer may have “little to do with phones.”

“Students are people and people are complicated,” she says. “Their achievement, engagement, and well-being are [likely] determined not by one thing, but by many. If you take away a distraction like a cell phone, it does not necessarily fix every other problem. Other questions surface. Is the school curriculum on point and engaging? Do teachers have adequate professional development? What is the quality of the overall culture in the school? Future research is likely to reveal important, but not simplistic, conclusions.”

As the team chooses which research questions to pursue next, they plan to draw on the strong network of partnerships they have established, and the conversations with educators they have launched and intend to continue.

“Principals are not asking: Should we ban phones or not? They are asking: How should we restrict them? What will that mean? When can the kids have them? How do we enforce these rules? How do we hold kids accountable? There’s a big set of questions that leaders, policymakers, and educators have to answer to meaningfully address this challenge,” says Duckworth. 

Gentzkow underscores the value of knitting those real-world questions into the research. “Had we entered schools as purely a team of academics, we may have been at risk of asking and answering the wrong set of questions. Collaborating with educators helped us understand where to focus, from the perspective of the people making real-world decisions about kids’ well-being every day.”

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