Explore the evidence
2 of 88 decisions · clear everything
Survives the gold standardIndependent, durable, rigorousThe debunked shelfCheap winsFor parents at homeFamous numbers, deflatedWhere we admit ignoranceThe terrain
domain
- math6
- reading6
- early childhood5
- health4
- debunked3
- practice3
- arts2
- foreign language2
- grouping2
- history civics2
- instruction style2
- motor skills2
- practical2
- time2
- assessment1
- behavior1
- character1
- class size1
- curriculum1
- deliberate practice1
- feedback1
- mastery1
- physical development1
- retention1
- school structure1
- sport1
- talent1
- teachers1
- transfer1
- tutoring1
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
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
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
Not yet assessed for this question · 1
The URL is the state — any view you build here is a permalink you can hand to someone mid-argument.