Grade 1 and Grade 2 domain-specific vocabulary knowledge explained 69% of the MORE intervention's treatment effect on Grade 2 domain-specific reading comprehension¶

Claim · All claims
Evidence · 1 study · causal r2 · q3
Currency · newest study 2024 · checked against its sources 2026-10-23 (automated, 1 of 1 entry) · not reviewed by a person

Subclaims¶

q3 i? Students' domain-specific vocabulary knowledge in Grades 1 and 2 mediated the treatment effect on domain-specific reading comprehension, explaining 69% of the relation. → Mosher 2024

Evidence¶

Mosher 2024¶

Mosher, D. M., Burkhauser, M. A., & Kim, J. S. (2024). Improving second-grade reading comprehension through a sustained content literacy intervention: A mixed-methods study examining the mediating role of domain-specific vocabulary. Journal of Educational Psychology, 116(4), 550–568. https://doi.org/10.1037/edu0000868

q3 · i? · causal · r2

SEM mediation analysis of the longitudinal RCT cohort (N = 2,156; 1,176 treatment, 980 control) from 30 stratified-randomized schools, clustering standard errors at the teacher level. The article reports the mediation hypothesis "was supported by the data, with Grade 1 and Grade 2 vocabulary knowledge explaining 69% of the relation." No standardized effect size is printed for the overall mediated proportion.

"Our hypothesis that domain-specific vocabulary knowledge mediates the relationship between the intervention and domain-specific reading comprehension was supported by the data, with Grade 1 and Grade 2 vocabulary knowledge explaining 69% of the relation."

Discussion¶

Learner Variables¶

• Prior Knowledge — predictor: learners who differ on it differ in outcomes
• Reading and Language — outcome: instruction changes it
• Vocabulary — predictor: learners who differ on it differ in outcomes

Related Claims¶

• The treatment effect on domain-specific reading comprehension was indirect-only: the direct path from treatment to comprehension was not significant — related
• Grade 1 vocabulary carried the significant mediated pathway, while treatment showed no significant direct path to Grade 2 vocabulary — related
• Treatment teachers reported providing more incidental exposure to target vocabulary than control teachers (ES = .54) — related
• Baseline reading and untaught Grade 2 vocabulary scores correlated moderately with near-, mid-, and far-transfer comprehension outcomes — related
• Teachers with high incidental exposure described expanded opportunities for word use and connecting words to topics — related