Changing How Literacy Is Taught: Evidence on Synthetic Phonics
Machin, S., McNally, S., & Viarengo, M. · 2018
grade Bnatural-experimentindependentreplicatednumbers spot-checked
Sample
Whole-population England pupil census (millions of pupils, cohorts 2005-2010)
Population
England state-school pupils tracked ages 5-11; subgroups FSM (low-income) and EAL (non-native).
Design
Difference-in-differences on the staggered rollout of England's CLLD synthetic-phonics teacher-training programme (early- vs later-adopting local authorities). A low-cost intervention retraining existing teachers. Cleanest at-scale identification in the phonics-policy literature.
Key findings
The corroborating natural experiment. Real early reading gains (0.22-0.30 SD at age 5) fade to ~0 on population average by age 11, persisting only for disadvantaged/EAL pupils (0.05-0.18 SD). Reproduces the RCT signature at national scale: modest, decoding-specific, fadeout-prone, durable mainly for the at-risk tail.
Genetic confound
Quasi-experimental staggered adoption; treatment assigned at LA/school level, not pupil self-selection - addresses passive rGE.
Replication notes
Pattern (early gain + mean fadeout + at-risk persistence) converges with Reading First RD (Gamse 2008) and Suggate 2016.
DOI / URL
10.1257/pol.20160514
Effects
| Outcome | Metric | Value | Measure | Timing | Vs | Horizon | Class |
|---|---|---|---|---|---|---|---|
| Reading, age 5 (end of treatment) | SD | +0.22 to +0.30 | mixed | end-of-treatment | business-as-usual | end-of-treatment | domain-skill |
| Reading, age 7 | SD | ~+0.08 (attenuating) | standardized | 2yr follow-up | business-as-usual | 1-2yr | domain-skill |
| Reading, age 11 (whole population) | SD | ~0.00 (mean fadeout) | standardized | 6yr follow-up | business-as-usual | over-2yr | domain-skill |
| Reading age 11, disadvantaged FSM / EAL subgroups | SD | +0.05 to +0.18 (persists) | standardized | 6yr follow-up | business-as-usual | over-2yr | domain-skill |
Cited by
- Systematic/explicit phonics vs whole language and balanced literacystrong supportconf: highgc: low