Explore the evidence
11 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
Testing yourself beats rereading — robust in real classrooms; honest durable size ~0.1–0.3 SD, biggest after delay, thinnest on transfer.
strong supportconf: highgc: lowRetrieval practice (the testing effect) · practice · ages 8–18 · method
Spacing beats massing at equal total time — the most robust finding in learning science. Space repetitions at ~10–20% of how long you need to remember.
strong supportconf: highgc: lowSpaced (distributed) practice · practice · ages 6–18 · method
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
Curriculum is nearly free, so choosing beats not choosing — but the payoff is avoiding a demonstrated loser, not finding a magic winner. Content is the high-upside bet.
mixedconf: highgc: lowCurriculum choice as a school-level lever · curriculum · ages 4–14 · structure
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
Mixing problem types helps where confusion is the enemy — discriminating similar categories, mixed math practice — and is useless or worse for facts and prose.
moderate supportconf: mediumgc: lowInterleaving (mixing problem types vs blocking) · practice · ages 10–18 · method
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
Sort by what the software replaces: adaptive drill inside the school day buys +0.05-0.20 SD; a device, a connection or the teacher buys zero to negative; LLM tutors have no usable evidence at all.
mixedconf: mediumgc: lowDoes educational technology raise learning — CAI, adaptive software, devices, screens, and AI tutors? · edtech · ages 5–18 · structure
The URL is the state — any view you build here is a permalink you can hand to someone mid-argument.