Standardize objective screen metrics

Researchers and platform companies should prioritize device‑derived, standardized measures of what adolescents actually do on screens (app categories, time‑stamped exposure, content types) instead of relying on self‑reported ‘screen time’. Agreement on standard metrics and shared, privacy‑preserving data pipelines would let studies compare effects across populations and isolate harms tied to content or context. — Better, standardized objective measures would collapse much of the current uncertainty, change the terms of policy debates (from blanket bans to targeted interventions), and make evidence actionable for regulators, schools and parents.