Explore the evidence
1 of 88 decisions · clear everything
Survives the gold standardIndependent, durable, rigorousThe debunked shelfCheap winsFor parents at homeFamous numbers, deflatedWhere we admit ignoranceThe terrain
Your situation · from the applicability layer — absence means “not yet assessed,” never “doesn’t apply”
who's delivering
group / setting
outcome class
Coaching buys ~0.25 SD of score and has for 42 years — a fraction of what's advertised — and none of it is ability. The score moves; the construct doesn't.
mixedconf: mediumgc: medium20/2036/48
Test preparation — does coaching raise scores, and does a raised score mean raised ability? · assessment · ages 5–18 · structure
Not yet assessed for this question · 10
- Acceleration and gifted programs — the label vs the content
- Class-size reduction
- Curriculum choice as a school-level lever
- Fadeout — why early gains disappear, and what actually persists
- Ability grouping and tracking — four practices, four verdicts
- 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
- Teacher quality — selection over credentials and workshops
The URL is the state — any view you build here is a permalink you can hand to someone mid-argument.