Banning cellphones was supposed to improve many of the problems ailing American education, including distraction, bullying, declining test scores and absenteeism.
The idea attracted rare, bipartisan support, and over the past three years, two-thirds of states passed laws restricting cellphones in schools.
But the bans have achieved only some of the goals that educators and parents hoped for, at least so far, according to a new study, the largest of its kind, which will be published Monday by the National Bureau of Economic Research.
Schools that adopted strict bans — requiring students to keep their devices in locked pouches throughout the school day — saw a meaningful decline in student cellphone use. But test scores have not increased in those places on average. And at first, banning phones led to higher suspension rates.
Still, teachers have been thrilled with the change, reporting fewer distractions from personal cellphone use. Over time, students in schools with strict bans reported a greater sense of personal well-being.
The paper, from researchers at Stanford, Duke, the University of Pennsylvania and the University of Michigan, relied on data from Yondr, a company that makes cellphone pouches that lock with a special magnetic device. Students are required to place their cellphones into individual pouches when they arrive at school. Students hold onto their pouches, but cannot unlock them until the last bell rings.
Researchers compared schools that use Yondr with demographically similar schools without pouches. Those control-group schools also typically limited cellphone use, but less strictly. They sometimes allowed students to use phones between classes, or to keep them as long as they stayed hidden from view. Cellphone use declined at those schools, too, but not by nearly as much as the ones that used Yondr, according to GPS data and teacher surveys.
Overall, the researchers looked at over 40,000 schools between 2019 and 2026. The study is based on a wide range of sources, including test scores, discipline reports, GPS data, and surveys of teachers and students.
It found that cellphone pings from school grounds declined by 30 percent in the first three years after schools adopted Yondr pouches. That is a meaningful shift, and was most likely caused by students losing access to their devices. Adults were still able to use their cellphones at school, and locked phones can still send and receive pings, such as when a text message or email is delivered.
The share of students using cellphones in class for nonacademic reasons declined to 13 percent from 61 percent in schools using the pouches, according to teacher surveys, which suggested that students were not widely able to circumvent the bans.
Even so, the bans had a “close to zero” effect on test scores, according to the paper. Test scores are affected by many factors, including the stability of students’ home lives and the quality of teaching and curriculum. The researchers also noted that once cellphones had been banned, students might have been distracted by other forms of technology, such as laptops, which are ubiquitous in American classrooms.
The bans also did not improve student attendance or perceptions of online bullying. And in the first year after strict bans went into place, student suspensions increased by an average of 16 percent — a large and troubling change.
The paper cannot pinpoint exactly why suspensions went up after schools began using Yondr pouches. The authors posited that some students were getting into trouble for violating the bans, while others were experiencing more peer conflict because they were “no longer self-anesthetizing” through their phones, said Thomas S. Dee, one of the authors and an education economist at Stanford.
Problems with student discipline faded over subsequent years.
Overall, Professor Dee said, he considered the study an “encouraging” early report on strict cellphone bans. He warned against abandoning a broadly supported policy because test scores did not immediately go up, or because implementation presented disciplinary challenges.
“There is a long history of faddish reforms in education that wink in and out of existence,” he said.In a written statement, Yondr said the company had been proud to participate in the first national, independent study of cellphone bans. “As with any change in school culture, there is an initial adjustment period, but the research confirmed that schools quickly move beyond these early challenges to see lasting benefits,” the statement read.
In Cape Girardeau, Mo., the deputy superintendent, Brice Beck, said his district was thrilled with its Yondr pouches, which had become a potent tool for attracting and retaining skilled teachers eager to work in more focused classrooms.
Even more exciting, he said, was the change adults had observed in teenagers’ social lives — something that cannot be measured in test scores.
“At lunch you will see all these kids, they’re talking to one another,” Dr. Beck said. “It’s a lot louder, but the good kind of loud.”
