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.
6 of 46 studies
- Design
- Randomized trial
- Grade bands
- 3–5
- Subjects
- Math
- Sample
- About 290 at-risk 4th graders
- Compared with
- School's usual fraction teaching
- Found
- Better on fraction comparison, number line, calculations, and released NAEP items.
- Limits
- At-risk students only.
- Design
- Randomized trial
- Grade bands
- 3–5
- Subjects
- Math
- Sample
- 277 at-risk 4th graders, 49 classrooms, 14 schools
- Compared with
- Usual teaching
- Found
- Gains on NAEP fraction items and number line.
- Limits
- Researcher-developed program.
- Design
- Randomized trial
- Grade bands
- 3–5
- Subjects
- Math
- Sample
- 213 at-risk 4th graders
- Compared with
- Usual teaching
- Found
- Better understanding and calculation; gains explained by better fraction-size understanding.
- Limits
- Small groups, not whole class.
- Design
- Review or practice guide
- Grade bands
- 3–5
- Subjects
- Math
- Sample
- Five trials with at-risk 4th graders
- Compared with
- —
- Found
- Consistent effects across five years of trials.
- Limits
- Same research group.
- Design
- Randomized trial
- Grade bands
- 3–5
- Subjects
- Math
- Sample
- 225 at-risk 4th graders
- Compared with
- Usual teaching
- Found
- Gains transferred to decimals without decimal instruction.
- Limits
- Same research group.
- Design
- Correlation
- Grade bands
- 3–5, 9–12
- Subjects
- Math
- Sample
- U.S. and U.K. longitudinal samples
- Compared with
- —
- Found
- 5th grade fraction and division knowledge predicted high school algebra and overall math, after accounting for IQ, reading and family income.
- Limits
- Not causal.