Cross-Study Differences in the Etiology of Reading Comprehension: A Meta-Analytical Review of Twin Studies
Little, C. W., Haughbrook, R., & Hart, S. A. · 2017
grade Ctwin-adoptionindependentunreplicated
Sample
Meta-analysis of reading-comprehension twin studies
Population
Twin samples across grades.
Design
Meta-analysis of behavioral-genetic decompositions of reading comprehension, with grade as a moderator.
Key findings
Reading comprehension is substantially heritable (h2=0.59) and becomes MORE so with age (+0.07/grade) as the shared-environment component instruction loads onto shrinks toward zero (-0.06/grade). This is the genetic mechanism for why early comprehension gains revert to a genetically-anchored trajectory - it strengthens the fadeout verdict.
Genetic confound
Genetically-sensitive; supplies the mechanism for comprehension-instruction fadeout.
Replication notes
The heritability-of-comprehension meta requested to bound durable population gains.
Effects
| Outcome | Metric | Value | Measure | Timing | Vs | Horizon | Class |
|---|---|---|---|---|---|---|---|
| Reading comprehension heritability | h2 | 0.59 (0.55-0.63); c2=0.16; e2=0.29 | standardized | cross-sectional | none | not-applicable | domain-skill |
| Change with grade | trend | h2 rises ~+0.07/grade; shared-environment c2 falls ~-0.06/grade | standardized | longitudinal | none | not-applicable | domain-skill |
Cited by
- Systematic/explicit phonics vs whole language and balanced literacystrong supportconf: highgc: low