Phones impede learning: Evidence from a massive phone-free classroom experiment

Preregistered RCT in Indian higher education (Science): mandatory in-class phone collection raised end-of-semester GPA ~0.073 SD vs free access; gains larger for lower prior performers and first-years. C6 kill-condition test survived 2026-10-14.

Indian HEI RCT (Science): collecting phones in lectures raised end-of-semester GPA, with larger and significant gains below median prior achievement and near-zero, non-significant effects above. Higher education, not school pupils.