Explore the evidence
4 of 88 decisions · clear everything
Survives the gold standardIndependent, durable, rigorousThe debunked shelfCheap winsFor parents at homeFamous numbers, deflatedWhere we admit ignoranceThe terrain
domain
Your situation · from the applicability layer — absence means “not yet assessed,” never “doesn’t apply”
who's delivering
outcome class
The received wisdom that retention is harmful was two measurement errors, not a finding. Fix them and the achievement effect is zero — but the grade at which you hold a child back decides everything.
mixedconf: mediumgc: low19/1936/48
Grade retention — holding a child back versus promoting, and test-based promotion policies · retention · ages 5–18 · structure
Classroom order is causally worth a great deal — one disruptive peer costs classmates 3% of adult earnings — yet no branded behaviour programme reliably delivers it and exclusion makes things worse.
mixedconf: mediumgc: low25/2536/48connected:Talent and trainabilityCan executive function be trained,Should a school buy a social and eAre self-control and grit teachabl
How should a school run its classrooms and its discipline system? · behavior · ages 4–18 · structure
Taking time away hurts measurably; adding it back buys almost nothing. The return per hour is ~0.02-0.03 SD, concave, and near zero in disorderly classrooms.
mixedconf: mediumgc: low23/2338/48
Length of the school day and year, time-on-task, extended time, and summer · time · ages 4–18 · structure
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: low21/2124/48
What a standardized achievement score does and does not license · assessment · ages 5–18 · structure
Not yet assessed for this question · 19
- Acceleration and gifted programs — the label vs the content
- Class-size reduction
- Curriculum choice as a school-level lever
- Deliberate practice and the 10,000-hour rule
- Explicit instruction vs discovery/inquiry — how much guidance?
- Fadeout — why early gains disappear, and what actually persists
- Feedback and formative assessment
- Ability grouping and tracking — four practices, four verdicts
- Interleaving (mixing problem types vs blocking)
- Mastery learning (teach → test → reteach to criterion → advance)
- Preschool at scale — Head Start, state pre-K, and what universal provision delivers
- Perry Preschool and Abecedarian — what the famous studies actually establish
- Retrieval practice (the testing effect)
- School spending, charters, and what school-level choices actually move outcomes
- School starting age, relative age, and academic redshirting
- Spaced (distributed) practice
- Teacher quality — selection over credentials and workshops
- Tutoring — the honest effect, the Bloom 2-sigma myth, and what survives scale
- Worked examples (studying solutions vs solving problems)
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