The Evidence on Teaching

Explore the evidence

8 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
group / setting
cost
outcome class

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: low
10/1018/48connected: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: low
7/712/48connected:Interleaving (mixing problem typesMath-fact fluency and timed practiRetrieval practice (the testing ef

Spaced (distributed) practice · practice · ages 6–18 · method

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

Mixing problem types helps where confusion is the enemy — discriminating similar categories, mixed math practice — and is useless or worse for facts and prose.

moderate supportconf: mediumgc: low
7/718/48connected:Spaced (distributed) practiceScience content sequencing

Interleaving (mixing problem types vs blocking) · practice · ages 10–18 · method

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: medium
14/1439/48

Chronic absenteeism — does raising attendance raise achievement? · time · ages 4–18 · input

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: medium
16/1629/48

Homework — effects by age and by dosage · homework · ages 5–18 · 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: low
23/2338/48

Length of the school day and year, time-on-task, extended time, and summer · time · ages 4–18 · structure

The URL is the state — any view you build here is a permalink you can hand to someone mid-argument.