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
- Meta-analysis
- Grade bands
- K–2, 3–5
- Subjects
- Reading and ELA
- Sample
- Same studies as Ehri 2001
- Compared with
- Same
- Found
- Smaller but still positive effect, about d = 0.24.
- Limits
- Different coding choices.
- Design
- Meta-analysis
- Grade bands
- K–2, 3–5
- Subjects
- Reading and ELA
- Sample
- 38 experiments, 66 comparisons
- Compared with
- Unsystematic or no phonics
- Found
- d = 0.41; 0.55 when started early, 0.27 after first grade; effects lasted after instruction ended.
- Limits
- Mix of experimental and quasi-experimental studies.
- Design
- Trend data
- Grade bands
- K–2
- Subjects
- Reading and ELA
- Sample
- All Year 1 pupils in England
- Compared with
- Earlier years
- Found
- 58% met the standard in 2012, 82% in 2018.
- Limits
- Not causal; schools learn the test.
- Design
- Review or practice guide
- Grade bands
- K–2, 3–5
- Subjects
- Reading and ELA
- Sample
- Expert panel review of rigorous studies
- Compared with
- —
- Found
- Strong evidence for sound-letter links and decoding; moderate for daily connected text; minimal for academic language.
- Limits
- Panel judgments.
- Design
- Trend data
- Grade bands
- 3–5
- Subjects
- Reading and ELA, Math
- Sample
- 4th graders, state results
- Compared with
- Other states, demographics-adjusted
- Found
- First in the nation in 4th grade reading and math after adjustment; 49th in reading in 2013.
- Limits
- Not causal; many reforms at once.
- Design
- Review or practice guide
- Grade bands
- K–2, 3–5
- Subjects
- Reading and ELA
- Sample
- Response to the reanalyses
- Compared with
- —
- Found
- Effects of the reanalyzed size still matter in practice.
- Limits
- Commentary.