Does banning cell phones at school improve student performance? This is one of the most debated questions in education in recent years. A study published by the NBER (National Bureau of Economic Research), in the United States, brings large-scale data to stimulate this discussion, and the results are more complex than many expected.
The research analyzed almost 5,000 American public schools that adopted sealable bags that prevent access to cell phones throughout the school period. Students keep the device in their bag when they arrive and can only remove it when leaving. The study was conducted by researchers from Stanford, Duke, Penn and Michigan, and the data covers the period from 2023 to 2025.
What are sealable bags and how do they work?
The bags are fabric cases with magnetic locks. The student places their cell phone inside when entering school, and the bag can only be opened on magnetic bases scattered around the environment, generally at the end of the shift or in emergencies. The device remains with the student, but is inaccessible.
This model of physical restriction is considered stricter than policies such as “leave your cell phone in your backpack” or “no use in the classroom”. Therefore, it was chosen as the object of the study: it allows us to measure more precisely what happens when access to the cell phone is actually prevented.
Cell phones at school: what the study found
The first result is clear: the grants worked to reduce usage. GPS data showed an approximately 30% drop in device activity within schools after adoption.
Teachers reported an even greater reduction: from 61% to 13% of students using their cell phones in class for personal purposes, indicating a drop of almost 80%.
But what did this restriction do to students beyond the use itself?
- Notes: the average effect on academic performance was close to zero; in secondary schools, there was a slight improvement in mathematics, while in the final years of primary school, there was a slight worsening. The researchers conclude that the two effects cancel each other out on the overall average.
- Well-being: In the first year after adoption, students’ subjective well-being fell: the drop was approximately 0.2 standard deviations, which is considered somewhat significant. Over time, however, the indicator recovered and became positive in the second year. The authors interpret this trajectory as a period of adaptation to the change in routine.
- Discipline: Disciplinary incidents increased by approximately 16% in the year of implementation and the effect also decreased over time.
- Frequency and attention: there were no significant changes.
- Online bullying: no significant changes were detected.
Why haven’t the grades improved?
The researchers point out some hypotheses. One of them is that, by removing their cell phones, students began to distract themselves in other ways, such as talking more with colleagues, for example. Another possibility is that, in some schools, the removal created gaps in the teaching process.
There are also differences between age groups. Younger students, with less impulse control, may have replaced their cell phones with similarly distracting behaviors. In high school, where use was more intense, the restriction generated modest gains, especially in mathematics.
The authors are cautious in interpreting this data: the study observed schools for a maximum of three years after adoption. Long-term effects are still unknown.
What parents and students think
The study also polled parents and students in a separate survey. Parents, for the most part, , relationships and mental health. Students, on the other hand, are against it and estimate that the benefits will be smaller than their parents project.
This divergence of expectations is relevant for those who make decisions about school policy. The evidence shows that neither the most optimistic (parents) nor the most skeptical (students) are completely right.
What the study means for the cell phone debate at school
Brazil is also at the center of this debate. of basic education throughout the national territory, making it one of the most comprehensive pieces of legislation in the world on the subject.
The does not offer definitive answers, but it brings concrete evidence to a discussion that is often marked by polarized opinions. Restricting cell phones, in itself, is not a magic solution for school performance, but it can contribute to a healthier environment — as long as schools are prepared to deal with the adaptation period.
As the researchers themselves highlight: the debate about the use of cell phones at school is still under construction. What we know so far is that prohibiting is not enough: we need to know what comes after the prohibition.
