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Survives the gold standardIndependent, durable, rigorousThe debunked shelfCheap winsFor parents at homeFamous numbers, deflatedWhere we admit ignoranceThe terrain
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Neither acceleration mandates nor delay mandates work — readiness-matched placement does. Push everyone and the median falls; hold everyone back and the top falls.
mixedconf: highgc: lowAlgebra timing — acceleration mandates, delay mandates, and readiness-based placement · math · ages 11–18
Feedback on the task helps modestly; feedback on the person backfires — a stable third of measured effects reverse. The famous 0.4–0.7 number has no computed source.
mixedconf: highgc: low18/1821/48connected:Retrieval practice (the testing efDoes teaching music produce musicaPlacement and mastery diagnosis
Feedback and formative assessment · feedback · ages 5–18 · method
Later bells buy adolescents 40+ measured minutes of sleep — the best-identified positive effect in the archive; the achievement payoff is real but far smaller.
strong supportconf: mediumgc: low18/1836/48
Do later school start times increase adolescent sleep, and does that raise achievement? · health · ages 11–18 · input
Selective CTE high schools raise male graduation 8-10pp and early-career earnings 17-35% on lottery and cutoff designs; test scores, degrees, and every outcome for girls are flat.
moderate supportconf: mediumgc: lowDo career and technical education tracks help students — and which students? · practical · ages 14–18
Immersion costs nothing in English and buys a little — a lottery puts English reading 0.13-0.22 SD ahead by grades 5 and 8 — but no lottery has ever measured how much of the second language students actually learn.
moderate supportconf: mediumgc: low8/824/48
Does dual-language immersion work, and is the gain in the second language or in English? · foreign-language · ages 4–18
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 URL is the state — any view you build here is a permalink you can hand to someone mid-argument.