The Evidence on Teaching

Explore the evidence

7 of 88 decisions · 3 collapse at your settings · 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
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Your situation · from the applicability layer — absence means “not yet assessed,” never “doesn’t apply”
who's delivering
group / setting
cost
outcome class

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: lowinsufficient at your settings
1/711/48connected:Does homeschooling raise achievemeSpaced (distributed) practiceWord problems, schema instruction,

Math-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: low
2/1021/48connected:Explicit instruction vs discovery/

Explicit 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: lowinsufficient at your settings
0/78/48connected:Math-fact fluency and timed practiWorked examples (studying solution

Word 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: low
6/936/48connected:Acceleration and gifted programsSchool starting age, relative age,

Algebra timing — acceleration mandates, delay mandates, and readiness-based placement · math · ages 11–18

The textbook matters at the bottom, not the top: avoid the demonstrated losers; mainstream choices now differ by ~0.02 SD.

mixedconf: highgc: low
4/1124/48connected:Background knowledge and vocabularSchool spending, charters, and wha

Math curriculum choice — how much does the textbook matter? · math · ages 5–14

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: lowinsufficient at your settings
0/36/48

Manipulatives and concrete-representational-abstract (CRA) sequences · math · ages 5–14

Near-zero in primary and almost entirely correlational in secondary. The causal base is three small trials; what the homework IS beats how much of it there is.

mixedconf: mediumgc: medium
6/1629/48

Homework — effects by age and by dosage · homework · ages 5–18 · structure

The URL is the state — any view you build here is a permalink you can hand to someone mid-argument.