Explore the evidence
15 of 88 decisions · clear everything
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
Explicit code teaching beats little-or-no-phonics for word reading — largest in K-1 and at-risk readers; near-null for comprehension and past grade 3. The whole-language contrast is real but the smallest measured.
strong supportconf: highgc: lowSystematic/explicit phonics vs whole language and balanced literacy · reading · ages 4–9
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
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 famous faded-feedback demo doesn't survive meta-analysis; mental practice is real at half the advertised size and never substitutes for physical practice.
mixedconf: highgc: lowFeedback frequency and mental practice in motor learning · motor-skills · ages 4–18
Mastery learning moves tests of what it taught (~0.25) and barely moves independent measures (~0.05) — and time-to-mastery gaps widen, converting ability differences into time.
mixedconf: highgc: lowMastery learning (teach → test → reteach to criterion → advance) · mastery · ages 6–18 · method
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
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
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
Diagnose what a child already knows: teachers cut 40–50% of curriculum for high-ability children and achievement ROSE. The payoff is skipping, not monitoring.
moderate supportconf: mediumgc: mediumPlacement and mastery diagnosis — deciding what to teach next from evidence of current skill · assessment · ages 5–18 · structure
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
One systematic review kept 39 studies from 11,771 records; another found 1 RCT among 53. What evidence exists favours interest (+0.12) over attainment (+0.01), and simulations match real apparatus.
mixedconf: mediumgc: lowLaboratory and practical work in school science · science · ages 5–18
Strategy instruction is a one-time boost, not a trainable skill: six sessions buy what fifty do, and modern at-scale trials are ~null.
mixedconf: mediumgc: lowReading-comprehension strategy instruction (reciprocal teaching, summarizing, questioning) · reading · ages 8–14
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
- Does arts education raise academic achievement?
- Does working-memory or brain training transfer to intelligence and achievement?
- Does learning to code improve general thinking?
- Can executive function be trained, and does it transfer to learning?
- Physical activity as an input — dose, fitness, and school outcomes
- Does teaching grammar improve children's writing?
- Does matching instruction to a child's "learning style" improve learning?
- Brain Gym, Whole Brain Teaching, and the smaller classroom brain fads
- Does teaching movement transfer to cognition, achievement, or lifelong activity?
- Should Gardner's multiple intelligences be used as a basis for instruction?
- Phonemic awareness training (and whether it needs letters)
- Teaching students to think scientifically — does it transfer?
- Early sport specialization, talent selection, and the relative age effect
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