The purpose of this study was to identify the effects of writing instruction studies for students
with learning disability and low achievement in Korea. We conducted a meta-analysis with R on
writing instruction studies. We calculated SMD(Standardized Mean Difference) for 20 quantitative
writing instruction studies. First, we identified a statistically large effect : total studies(SMD = 1.49),
the studies on low achievement(SMD = 1.69), and studies on learning disabilities(SMD =1.10).
Second, we found that cooperative learning(SMD = 2.69), CAI(SMD = 0.92) and total language
learning method(SMD = 1.34) resulted in a statistically significant large effect. Finally, total studies,
studies on low achievement, cooperative learning and CAI' heterogeneity was large, but studies on
learning disability and total language learning' heterogeneity was small. Findings of this study
suggested that cooperative learning, CAI and total language method can be effective in promoting
writing ability for students with low achievement or learning disability.