School phone policies and their association with mental wellbeing, phone use, and social media use (SMART Schools): a cross-sectional observational study

Which beliefs it touches

• C6 Phones in lessons sets a limit on it

  Cross-sectional comparison of 20 restrictive vs 10 permissive English secondary schools (1,227 pupils aged 12–15): no significant difference in teacher-rated odds of being below target in English (adjusted OR 1.45, 95% CI 0.85–2.47, p = 0.18) or maths (1.01, 0.45–2.27, p = 0.98). Not a before/after or randomised design; attainment is a teacher rating, not a test score.

• C36 Phone bans and lower achievers sets a limit on it

  Same study does not split the policy contrast by prior achievement, so it cannot test whether lower-achieving pupils gain more.