Explore the evidence
13 of 88 decisions · clear everything
- math6
- reading6
- writing6
- early childhood5
- science5
- arts4
- character4
- health4
- assessment3
- debunked3
- foreign language3
- history civics3
- homeschool3
- practice3
- grouping2
- instruction style2
- motor skills2
- music2
- practical2
- time2
- transfer2
- behavior1
- class size1
- computer science1
- curriculum1
- deliberate practice1
- edtech1
- feedback1
- homework1
- mastery1
- physical development1
- retention1
- school structure1
- sport1
- talent1
- teachers1
- tutoring1
Teaching movement teaches movement: the skills improve, but transfer to cognition, achievement, or lifelong activity is near zero in the best trials.
no effectconf: highgc: mediumDoes teaching movement transfer to cognition, achievement, or lifelong activity? · physical-development · ages 4–18
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: lowDo later school start times increase adolescent sleep, and does that raise achievement? · health · ages 11–18 · input
Teaching handwriting works and transfers: freeing the hand frees composition, with gains still present at six months — even taught in groups of three.
moderate supportconf: mediumgc: mediumDoes handwriting and transcription instruction matter, and should young children type instead? · writing · ages 5–12
Sentence combining improves writing where grammar teaching fails — the same meta-analyses score them +0.50 and −0.32.
moderate supportconf: mediumgc: lowDoes sentence combining improve writing? · writing · ages 5–18
Strategy instruction is writing's best-supported method — at roughly a fifth of its advertised size once measures are independent (d≈0.8 → ~0.15).
moderate supportconf: mediumgc: lowDoes strategy instruction (SRSD, the writing process) improve writing? · writing · ages 5–18
Teaching coding teaches coding: the one clean school RCT gives g=0.47-0.68. Which approach you pick barely matters, and almost every effect size rests on an instrument the developers built.
moderate supportconf: mediumgc: lowDoes teaching programming actually teach programming — and does the method matter? · computer-science · ages 5–18
Formal spelling instruction works (ES 0.54) and more formal beats less formal — explicit wins again, and it transfers beyond spelling itself.
moderate supportconf: mediumgc: lowDoes teaching spelling work, and what does it transfer to? · writing · ages 5–18
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: lowVision — 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: lowBreakfast, school meals, and micronutrients — what feeding children actually buys · health · ages 4–18 · input
Capitalisation and punctuation move when directly taught and directly measured, and don't move when embedded in writing programmes. A teachable subject, not a writing lever.
mixedconf: mediumgc: mediumCan capitalisation, punctuation and usage be taught directly as their own subject? · writing · ages 5–18
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: lowHow should a school run its classrooms and its discipline system? · behavior · 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: lowPhysical activity as an input — dose, fitness, and school outcomes · health · ages 4–18 · input
Teaching grammar does not improve writing at any age tested — and it displaces the things that do.
negativeconf: mediumgc: lowDoes teaching grammar improve children's writing? · writing · ages 5–18
The URL is the state — any view you build here is a permalink you can hand to someone mid-argument.