The Educational Impacts of School Phone Bans: Evidence from Brazil -- by Guilherme Lichand, Luca Moreno-Louzada, Thiago da Costa, Matthew Gentzkow

Concerns about negative impacts of student phone use have led to calls around the world for tighter restrictions on phones in schools. This paper evaluates the impact of a 2023 policy that banned non-pedagogical uses of phones within schools in Rio de Janeiro, Brazil. To isolate the causal effects of the policy, we contrast middle schools that already had strict rules on phone use prior to the policy ("control schools'') to similar schools that did not have strict rules ("treatment schools''), before and after the ban. While restrictions were imperfectly implemented both before and after the ban, we show that in-school phone use fell substantially in treatment schools relative to control. We then show that test scores, which were trending similarly in the two groups prior to the ban, improved by 0.06 s.d. in treatment schools relative to control.