The Effects of School Phone Bans: National Evidence from Lockable Pouches

Preregistered national US DiD (working paper, not peer reviewed): lockable phone pouches cut in-class phone use but average test-score effects were close to zero (rules out gains > ~0.007 student SD); high-school maths up, middle schools slightly down. C6 weakened 2026-10-07 (average-effect bound).

US pouch DiD (preprint): limited systematic heterogeneity in pre-registered subgroups; no positive pooled test-score effect for any subgroup examined; in middle schools, negative effects were more pronounced among higher-achieving schools (not pre-registered; school-level baseline achievement, not pupil-level).