The Evidence on Teaching

Explore the evidence

6 of 88 decisions · clear everything

Survives the gold standardIndependent, durable, rigorousThe debunked shelfCheap winsFor parents at homeFamous numbers, deflatedWhere we admit ignoranceThe terrain
evidencealldrop DA–BA only
evaluatoranyno dev-ledindependent
durabilityanyfollow-up≥1yr≥2yr
what are these? →
sortconfidencerobustfragileA–Z
domain
verdict
confidence
layer
Your situation · from the applicability layer — absence means “not yet assessed,” never “doesn’t apply”
who's delivering
  • nothing assessed yet
group / setting
  • nothing assessed yet
cost
  • nothing assessed yet
outcome class
  • nothing assessed yet

Early gains fade by default — halving every 12–18 months, faster when bigger. What persists is trajectory (placement, graduation), not ability.

strong supportconf: highgc: low
10/1048/48connected:Does working-memory or brain trainDoes learning to code improve geneCan executive function be trained,Does teaching a growth mindset rai+2

Fadeout — why early gains disappear, and what actually persists · early-childhood · ages 4–18 · structure

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: low
12/1236/48connected:Do career and technical education

Ability 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: medium
8/830/48connected:Algebra timing

Acceleration and gifted programs — the label vs the content · grouping · ages 5–18 · structure

At scale, pre-K doesn't durably raise test scores — Tennessee went negative — yet Boston shows real attainment gains beside a test-score zero. It buys trajectory, not ability.

mixedconf: highgc: low
17/1748/48connected:FadeoutPerry Preschool and Abecedarian

Preschool at scale — Head Start, state pre-K, and what universal provision delivers · early-childhood · ages 4–5 · structure

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: low
6/636/48connected:Algebra timing

School starting age, relative age, and academic redshirting · early-childhood · ages 4–7 · 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: low
8/836/48connected:Preschool at scale

Perry Preschool and Abecedarian — what the famous studies actually establish · early-childhood · ages 4–5 · structure

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