Explore the evidence
3 of 88 decisions · clear everything
Survives the gold standardIndependent, durable, rigorousThe debunked shelfCheap winsFor parents at homeFamous numbers, deflatedWhere we admit ignoranceThe terrain
domain
Your situation · from the applicability layer — absence means “not yet assessed,” never “doesn’t apply”
who's delivering
group / setting
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: low9/1836/48
Do later school start times increase adolescent sleep, and does that raise achievement? · health · ages 11–18 · input
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: low17/1936/48
Grade retention — holding a child back versus promoting, and test-based promotion policies · retention · ages 5–18 · structure
No study of homeschooling has a counterfactual — the famous percentile claims are selection all the way down. The honest answer: nobody knows.
insufficientconf: lowgc: high3/2336/48connected:Homeschool socialisationThe parent as instructorSystematic/explicit phonics vs whoMath-fact fluency and timed practi
Does homeschooling raise achievement and attainment, or does it select the children who would have done well anyway? · homeschool · ages 5–18 · structure
Not yet assessed for this question · 16
- Acceleration and gifted programs — the label vs the content
- Chronic absenteeism — does raising attendance raise achievement?
- Class-size reduction
- Curriculum choice as a school-level lever
- Physical activity as an input — dose, fitness, and school outcomes
- Fadeout — why early gains disappear, and what actually persists
- Ability grouping and tracking — four practices, four verdicts
- The early home environment — what parents can and cannot causally move
- Breakfast, school meals, and micronutrients — what feeding children actually buys
- Preschool at scale — Head Start, state pre-K, and what universal provision delivers
- Perry Preschool and Abecedarian — what the famous studies actually establish
- School spending, charters, and what school-level choices actually move outcomes
- School starting age, relative age, and academic redshirting
- Talent and trainability — what is heritable, and what that does not license
- Teacher quality — selection over credentials and workshops
- Vision — outdoor time against myopia, and screening and correction for achievement
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