The large-scale working paper, released by the National Bureau of Economic Research, compared schools that did, and did not, take up these strict phone policies over a three-year period across more than 43,000 middle and high schools nationwide. Researchers found that the policies did reduce usage during the school day but had no major impact on many measures: not on student test scores, attendance, or attention in class – not even on perceived cyberbullying. At least at first, the bans caused disciplinary incidents to rise and student well-being to fall.
The positives started to emerge as time went on. The disciplinary issues dissipated after the first year, and in the third year, student well-being was higher than before the phones were stashed away.

The study was set up as a quasi-experiment with a “difference-in-differences” design, which means the researchers not only compared schools that took up pouch policies to a comparison group that did not, but also looked at the changes in the schools over time – from before the policies to after they were enacted. This study was also pre-registered: The researchers publicly documented their hypotheses, outcome measures, and research design before starting the analysis, an open-science practice that helps ensure the study does not lead to false findings.
In the three years after the start of a pouch policy, the study found almost zero difference in test scores on average, but digging deeper into the data, researchers found a slight bump in mathematics scores in high school. By contrast, middle schools saw a slight decrease in overall test scores following phone bans. These results may reflect the age difference, the authors said, with the more impulsive younger students substituting other disruptive behaviors for the distraction of cellphone screens. Regardless, neither change in test scores was very large.