Project 04 · Series DV
The Device
Four layers of evidence, routinely argued as though they were one.
A device engineered for attention capture imposes a real and mechanistically understood cost, and it falls hardest on the students with the least spare self-regulatory capacity. Nothing in the recent evidence touches this layer.
Bar width is the weight of the evidence behind a layer, not the size of the effect. Select a layer to see what it will carry.
The first year looks like failure
Suspension rates in the adoption year, fading afterwards. Florida found the same shape at student level, and roughly 30 per cent among Black students.Allcott et al. (2026); Figlio & Özek (2025)
Both costs land in year one and both recover. A school that has not been told to expect that will read its own data as proof the policy failed, and reverse it in the term before it works.
Four numbers
Teacher-reported in-class phone use, before and after lockable pouches, across 1,777 schools.Allcott et al. (2026), NBER WP 35132
The average effect on test scores across three years.Allcott et al. (2026)
Studies in the meta-analysis that disputes the mere-presence claim.Hartanto et al. (2024)
Children’s Wellbeing and Schools Act 2026, in force since 29 June 2026.UK legislation