The studies
Reviewed · 1 min read
Every grade on this site rests on the studies in this table. Each row says what kind of study it was, who was studied, what it was compared with, what it found, and where it falls short. Filter by grade band, subject, design or principle.
How to read the design column, and why a correlation never earns a grade, is explained on How we grade the evidence.
This is the seed of a larger database. The plan is to add every randomized trial of a classroom practice in K–12, with the same columns, so that a reader never has to go to a second site to check a claim. New studies are logged monthly and reviewed quarterly; see Keeping it current.
2 of 46 studies
- Design
- Meta-analysis
- Grade bands
- adult
- Subjects
- general
- Sample
- 607 effect sizes
- Compared with
- No feedback
- Found
- Feedback raised performance on average, but over a third of interventions lowered it; feedback about the self hurt most.
- Limits
- Mostly adults and lab tasks.
- Principles
- Design
- Review or practice guide
- Grade bands
- K–2, 3–5, 6–8, 9–12
- Subjects
- general
- Sample
- Review of classroom applications of cognitive science
- Compared with
- —
- Found
- Classroom evidence is thinner than lab evidence; multi-strategy programs tested at scale often showed small effects; little early-years evidence.
- Limits
- Review, not pooled estimates.