Explore the evidence
2 of 88 decisions · clear everything
Survives the gold standardIndependent, durable, rigorousThe debunked shelfCheap winsFor parents at homeFamous numbers, deflatedWhere we admit ignoranceThe terrain
domain
verdict
confidence
layer
Your situation · from the applicability layer — absence means “not yet assessed,” never “doesn’t apply”
who's delivering
group / setting
cost
outcome class
Early specialization predicts junior success; later starts plus other sports predict adult world-class. Selecting on junior results selects the wrong athletes.
mixedconf: mediumgc: medium7/724/48
Early sport specialization, talent selection, and the relative age effect · sport · ages 6–18
The received wisdom that retention is harmful was two measurement errors, not a finding. Fix them and the achievement effect is zero — but the grade at which you hold a child back decides everything.
mixedconf: mediumgc: low19/1936/48
Grade retention — holding a child back versus promoting, and test-based promotion policies · retention · ages 5–18 · structure
The URL is the state — any view you build here is a permalink you can hand to someone mid-argument.