Meta-analysis of Reading Interventions for Primary-Grade Students with Reading Difficulties

This meta-analysis synthesized 47 studies (N=7446 students) examining the effects of foundational reading skills and multicomponent reading interventions on reading comprehension for primary-grade students (kindergarten to Grade 3) with or at risk for reading difficulties or disabilities (RDs). The overall weighted average effect on norm-referenced comprehension outcomes was g=0.37, indicating an educationally meaningful impact. Effects did not significantly differ between foundational skills-only and multicomponent interventions (foundational skills plus comprehension instruction). Measurement timepoint moderated effects, with follow-up effect sizes being 0.16 smaller than immediate posttest sizes. The study aimed to extend previous meta-analyses by including more recent research (up to August 2019) and examining intervention duration, instructional emphasis, dosage, and methodological factors.

Building on the 'simple view of reading' (reading comprehension = word recognition x linguistic comprehension), the meta-analysis explored whether interventions focusing on word reading, comprehension, or both are most effective. Previous research by Suggate (2010) and Wanzek et al. (2016) showed positive effects of reading interventions. This study specifically asked: (a) What is the main effect of small-group and individual foundational skills/multicomponent reading interventions on comprehension for K-3 students with RDs? (b) Are effects moderated by instructional focus (foundational skills-only vs. multicomponent)? (c) Are effects moderated by intervention dosage or methodological factors (study quality, measurement timepoint, type of comprehension measure)? There is preliminary evidence that adding comprehension instruction to word-level instruction might not always significantly improve outcomes for students with RDs beyond word-level instruction alone, a critical question given limited intervention time in schools.

The meta-analysis included studies from Wanzek et al. (2016, 2018) that met specific criteria, along with new studies published until August 2019. Inclusion criteria focused on small-group or individual interventions targeting K-3 students with RDs, using norm-referenced reading comprehension outcomes. The 47 included studies encompassed a total of 7446 students, with individual study sample sizes ranging from 24 to 881. Studies included participants from kindergarten (8 studies), first grade (34 studies), second grade (16 studies), and third grade (9 studies), with 14 studies including students from multiple grades. Factors like study quality, type of comprehension measure (cloze, passage with questions, sentence comprehension), and measurement timepoint (immediate posttest vs. follow-up) were investigated as potential moderators.

The meta-analysis confirmed that small-group or individually administered reading interventions have a significant and educationally meaningful effect (g=0.37) on norm-referenced reading comprehension for primary-grade students with RDs. While the overall effect is positive, the study found no significant difference in effectiveness between interventions focused solely on foundational reading skills and those that incorporated both foundational skills and comprehension instruction. This suggests that for primary-grade students with RDs, dedicating limited intervention time to foundational skills may be as effective for comprehension outcomes as broader multicomponent approaches. The study also highlighted that intervention effects tend to diminish over time, with follow-up effects being smaller than immediate post-intervention effects.