Explore the evidence
17 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
Timed retrieval practice builds arithmetic automaticity — beating identical untimed tutoring head-to-head — and the anti-timed-test harm claims have no causal evidence.
strong supportconf: highgc: lowMath-fact fluency and timed practice (and the anti-timed-test claims) · math · ages 5–12
Minimal-guidance math trailed every rival in the one multi-curriculum RCT; explicit instruction for strugglers is math's most replicated result.
moderate supportconf: highgc: lowExplicit vs reform/constructivist math instruction · math · ages 5–18
Word-problem solving is its own skill: computation fluency doesn't produce it. Teaching problem schemas explicitly does (~0.25–0.45 SD on trained content).
moderate supportconf: highgc: lowWord problems, schema instruction, and the conceptual-vs-procedural question · math · ages 6–14
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
Grit is conscientiousness renamed and adds 0.4% to grade prediction; self-control genuinely predicts life outcomes but is 60% heritable with zero shared environment, and training moves ratings, not lives.
mixedconf: highgc: mediumAre self-control and grit teachable levers on achievement? · character · ages 4–18
Growth-mindset interventions change beliefs almost everywhere and change achievement almost nowhere: the two independent national-scale trials measured standardized tests and found exactly zero.
mixedconf: highgc: lowDoes teaching a growth mindset raise achievement? · character · ages 4–18
The textbook matters at the bottom, not the top: avoid the demonstrated losers; mainstream choices now differ by ~0.02 SD.
mixedconf: highgc: lowMath curriculum choice — how much does the textbook matter? · math · ages 5–14
Should a school buy a social and emotional learning programme? · character · ages 4–18
Executive function trains like a task, not like a capacity: gains are real, narrow, and gone at follow-up, EF curricula are null under independent trial, and the latent construct is ~100% heritable.
no effectconf: highgc: lowCan executive function be trained, and does it transfer to learning? · character · ages 4–18
Yes, on their own terms: lottery-assigned museum and theatre trips move blind-rated analysis of art, plot knowledge and tolerance by 0.08-0.18 SD weeks later, and a film of the same play moves nothing.
moderate supportconf: mediumgc: lowAre museum and theatre trips worth the day out of school? · arts · ages 8–18
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: lowDoes dual-language immersion work, and is the gain in the second language or in English? · foreign-language · ages 4–18
Manipulatives help when bland, guided, and aged ~7–11 — a guided-representation effect, not 'hands-on learning.' Rich, toy-like objects hurt transfer.
moderate supportconf: mediumgc: lowManipulatives and concrete-representational-abstract (CRA) sequences · math · ages 5–14
Explicit form-focused teaching beats pure exposure, so the archive's negative verdict on L1 grammar does NOT transfer — but the effects are measured on the taught forms, immediately, mostly on adults.
mixedconf: mediumgc: lowComprehensible input or explicit grammar teaching — which builds a second language? · foreign-language · ages 4–18
The headline effects are a measurement artefact: drama gives d≈0.89 on researcher-made tests and d≈0.29 on standardized ones, and the two randomised trials with standardized outcomes are null.
mixedconf: mediumgc: mediumDoes classroom drama build verbal and literacy skills? · arts · ages 5–16
Attainment falls steadily with age of first exposure, but the sharp critical period is contested and an earlier classroom start buys nothing durable: start young for immersion, not for two lessons a week.
mixedconf: mediumgc: mediumIs there a critical period for learning a second language, and when should a child start? · foreign-language · ages 4–18
No. The two randomised programmes that tested it — 42 Houston schools and five EEF trials across 400 English schools — return nulls on reading and maths; only writing, the outcome nearest the treatment, moves.
no effectconf: mediumgc: lowDoes arts education raise academic achievement? · arts · ages 5–14
Nobody has tested it. There is no controlled trial in which art instruction is the input and independently measured art skill is the outcome — the field's core claim is the one it never studied.
insufficientconf: lowgc: mediumDoes teaching visual art produce artistic skill? · arts · ages 4–18
The URL is the state — any view you build here is a permalink you can hand to someone mid-argument.