Explore the evidence
13 of 88 decisions · clear everything
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
Starting school older mostly manufactures an age-at-test artifact: the IQ effect collapses to ~−0.07 once identified. Real residues: less hyperactivity, unchanged attainment.
mixedconf: highgc: lowSchool starting age, relative age, and academic redshirting · early-childhood · ages 4–7 · structure
Most measured 'home environment' effects are parents' genes: three-quarters of parent-child transmission isn't rearing, and a whole better childhood buys ~4 IQ points.
mixedconf: highgc: lowThe early home environment — what parents can and cannot causally move · early-childhood · ages 4–10 · input
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
Correcting a real deficiency moves cognition (iron in anaemic children: 0.79 SD); supplementing already-fed children moves nothing (35 RCTs, 19,343 children).
mixedconf: mediumgc: lowBreakfast, school meals, and micronutrients — what feeding children actually buys · health · ages 4–18 · input
A missed day costs little (~0.005 SD); interventions reliably buy days back cheaply, but nobody has shown the recovered days move achievement.
mixedconf: mediumgc: mediumChronic absenteeism — does raising attendance raise achievement? · time · ages 4–18 · input
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
Perry and Abecedarian: n=123 and n=111, IQ gains gone by adolescence, attainment effects real but multiplicity-fragile. Too thin to carry the policy built on them.
mixedconf: mediumgc: lowPerry Preschool and Abecedarian — what the famous studies actually establish · early-childhood · ages 4–5 · structure
What parents are asked to DO is the whole effect: tutoring a skill d≈1.15, listening to reading 0.51, reading aloud ~0.18 — same parent, same child. All deflate under better designs.
mixedconf: mediumgc: mediumThe parent as instructor — what survives when the person teaching is the person who raised the child · homeschool · ages 4–18 · method
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
No study of homeschooling has a counterfactual — the famous percentile claims are selection all the way down. The honest answer: nobody knows.
insufficientconf: lowgc: highDoes homeschooling raise achievement and attainment, or does it select the children who would have done well anyway? · homeschool · ages 5–18 · structure
Homeschoolers get plenty of social contact but measurably fewer, closer peer ties; whether that helps or harms has never been causally tested.
insufficientconf: lowgc: highHomeschool socialisation — the most-asked question, and the least answerable one · homeschool · ages 6–18 · structure
The URL is the state — any view you build here is a permalink you can hand to someone mid-argument.