The Evidence on Teaching

Explore the evidence

8 of 88 decisions · clear everything

Survives the gold standardIndependent, durable, rigorousThe debunked shelfCheap winsFor parents at homeFamous numbers, deflatedWhere we admit ignoranceThe terrain
evidencealldrop DA–BA only
evaluatoranyno dev-ledindependent
durabilityanyfollow-up≥1yr≥2yr
what are these? →
sortconfidencerobustfragileA–Z
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

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: low
18/1836/48

Do later school start times increase adolescent sleep, and does that raise achievement? · health · ages 11–18 · input

Outdoor time prevents myopia from starting (not progressing); screening plus free glasses raises test scores in children who need them. Two claims, both real.

moderate supportconf: mediumgc: low
17/1736/48

Vision — outdoor time against myopia, and screening and correction for achievement · health · ages 4–18 · input

Correcting a real deficiency moves cognition (iron in anaemic children: 0.79 SD); supplementing already-fed children moves nothing (35 RCTs, 19,343 children).

mixedconf: mediumgc: low
20/2018/48connected:Does teaching movement transfer to

Breakfast, school meals, and micronutrients — what feeding children actually buys · health · ages 4–18 · input

A missed day costs little (~0.005 SD); interventions reliably buy days back cheaply, but nobody has shown the recovered days move achievement.

mixedconf: mediumgc: medium
14/1439/48

Chronic absenteeism — does raising attendance raise achievement? · time · ages 4–18 · 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: low
19/1936/48

Grade retention — holding a child back versus promoting, and test-based promotion policies · retention · ages 5–18 · structure

Classroom order is causally worth a great deal — one disruptive peer costs classmates 3% of adult earnings — yet no branded behaviour programme reliably delivers it and exclusion makes things worse.

mixedconf: mediumgc: low
25/2536/48connected:Talent and trainabilityCan executive function be trained,Should a school buy a social and eAre self-control and grit teachabl

How should a school run its classrooms and its discipline system? · behavior · ages 4–18 · structure

Taking time away hurts measurably; adding it back buys almost nothing. The return per hour is ~0.02-0.03 SD, concave, and near zero in disorderly classrooms.

mixedconf: mediumgc: low
23/2338/48

Length of the school day and year, time-on-task, extended time, and summer · time · ages 4–18 · structure

School exercise programs don't raise achievement: four of the five largest RCTs are null, and more dose doesn't rescue it. Exercise for health, not for grades.

no effectconf: mediumgc: low
24/2429/48connected:Does teaching movement transfer to

Physical activity as an input — dose, fitness, and school outcomes · health · ages 4–18 · input

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