Explore the evidence
18 of 88 decisions · clear everything
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
Group within classes or across grades by subject: modest, nearly free wins. Whole-school streaming does nothing, and early between-school tracking harms the bottom.
moderate supportconf: highgc: lowAbility grouping and tracking — four practices, four verdicts · grouping · ages 5–18 · structure
Accelerate ready kids: they keep pace with older classmates, bank a year, and show no social-emotional harm at 50. The gifted label itself does nothing; the content does.
moderate supportconf: highgc: mediumAcceleration and gifted programs — the label vs the content · grouping · ages 5–18 · structure
Varied practice looks worse today and better at retention — in the lab. Applied settings shrink the edge to zero, and it reverses in under-18s.
mixedconf: highgc: lowPractice scheduling for motor skills — varied vs blocked, spaced vs massed · motor-skills · ages 4–18
Unallocated money is the worst buy in the database; the same dollars as No-Excuses charters buy +0.3–0.4 SD/yr — and the average charter is a precise null.
mixedconf: highgc: lowSchool spending, charters, and what school-level choices actually move outcomes · school-structure · ages 4–18 · structure
Should a school buy a social and emotional learning programme? · character · ages 4–18
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
Yes — sight-reading, performance and aural skill move about half a standard deviation under instruction — but the evidence is quasi-experimental and thinner than the transfer literature built on top of it.
moderate supportconf: mediumgc: mediumDoes teaching music produce musical skill? · music · ages 4–18
Novices learn faster studying solutions than solving problems — then the effect reverses with expertise. Use worked examples early; fade them.
moderate supportconf: mediumgc: lowWorked examples (studying solutions vs solving problems) · instruction-style · ages 10–18 · method
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
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
Document-based instruction reliably improves the sourcing and argument tasks it teaches (g ≈ 0.42) and, in the two best-identified trials, moves neither standardized reading nor history knowledge.
mixedconf: mediumgc: lowDoes document-based source work move history knowledge, reading comprehension, or neither? · history-civics · ages 8–18
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
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: mediumHomework — effects by age and by dosage · homework · ages 5–18 · structure
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
Conceptual-change teaching reliably moves the test and nothing shows it removes the intuition. Corrected for design and publication bias, a taught unit is g≈0.64 and a refutation text g≈0.28.
mixedconf: mediumgc: lowScience misconceptions and conceptual change — can naive intuitions be taught away? · science · ages 6–18
Trust the composite; distrust the breakdown. Subtest strengths-and-weaknesses replicate at chance on retest, and most of what people read off a score report is noise.
mixedconf: mediumgc: lowWhat a standardized achievement score does and does not license · assessment · ages 5–18 · structure
- Does arts education raise academic 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
- Explicit instruction vs discovery/inquiry — how much guidance?
- Does teaching grammar improve children's writing?
- Homeschool socialisation — the most-asked question, and the least answerable one
- Does teaching movement transfer to cognition, achievement, or lifelong activity?
- Phonemic awareness training (and whether it needs letters)
- Reading fluency — guided repeated oral reading, and whether repetition matters
- School starting age, relative age, and academic redshirting
- Teaching students to think scientifically — does it transfer?
- Vision — outdoor time against myopia, and screening and correction for achievement
- Early sport specialization, talent selection, and the relative age effect
The URL is the state — any view you build here is a permalink you can hand to someone mid-argument.