Explore the evidence
7 of 88 decisions · clear everything
Survives the gold standardIndependent, durable, rigorousThe debunked shelfCheap winsFor parents at homeFamous numbers, deflatedWhere we admit ignoranceThe terrain
domain
survival prior
Your situation · from the applicability layer — absence means “not yet assessed,” never “doesn’t apply”
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: low10/1018/48connected:Feedback and formative assessmentMastery learning (teach → test → rSpaced (distributed) practice
Retrieval 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: low7/712/48connected:Interleaving (mixing problem typesMath-fact fluency and timed practiRetrieval practice (the testing ef
Spaced (distributed) practice · practice · ages 6–18 · method
Unassisted discovery loses to explicit teaching; well-scaffolded guided discovery beats both. The operative variable is guidance, not ideology.
moderate supportconf: mediumgc: low13/1315/48connected:Worked examples (studying solutionExplicit vs reform/constructivist Science content sequencingInquiry-based science teaching vs +1
Explicit instruction vs discovery/inquiry — how much guidance? · instruction-style · ages 4–18 · method
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
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: medium16/1629/48
Homework — effects by age and by dosage · homework · ages 5–18 · structure
School exercise programs don't raise achievement: four of the five largest RCTs are null, and more dose doesn't rescue it. Exercise for health, not for grades.
no effectconf: mediumgc: lowPhysical activity as an input — dose, fitness, and school outcomes · health · ages 4–18 · input
No study of homeschooling has a counterfactual — the famous percentile claims are selection all the way down. The honest answer: nobody knows.
insufficientconf: lowgc: high23/2336/48connected:Homeschool socialisationThe parent as instructorSystematic/explicit phonics vs whoMath-fact fluency and timed practi
Does homeschooling raise achievement and attainment, or does it select the children who would have done well anyway? · homeschool · ages 5–18 · structure
Not yet assessed for this question · 20
- Acceleration and gifted programs — the label vs the content
- Chronic absenteeism — does raising attendance raise achievement?
- Class-size reduction
- Curriculum choice as a school-level lever
- Feedback and formative assessment
- Grade retention — holding a child back versus promoting, and test-based promotion policies
- Ability grouping and tracking — four practices, four verdicts
- Vision — outdoor time against myopia, and screening and correction for achievement
- The early home environment — what parents can and cannot causally move
- Homeschool socialisation — the most-asked question, and the least answerable one
- Length of the school day and year, time-on-task, extended time, and summer
- Interleaving (mixing problem types vs blocking)
- Breakfast, school meals, and micronutrients — what feeding children actually buys
- Placement and mastery diagnosis — deciding what to teach next from evidence of current skill
- Preschool at scale — Head Start, state pre-K, and what universal provision delivers
- Perry Preschool and Abecedarian — what the famous studies actually establish
- School spending, charters, and what school-level choices actually move outcomes
- School starting age, relative age, and academic redshirting
- Do later school start times increase adolescent sleep, and does that raise achievement?
- Teacher quality — selection over credentials and workshops
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