This meta-analysis extends previous work on extensive Tier 3 type reading interventions (Wanzek & Vaughn, 2007; Wanzek et al., 2013) to Tier 2 type interventions by examining a nonoverlapping set of studies addressing the effects of less extensive reading interventions for students with or at risk for reading difficulties in kindergarten through grade 3. The authors examined the overall effects of these interventions on students' foundational skills, language, and comprehension as well as the intervention features that may be associated with improved outcomes. The authors conducted four meta-analyses on 72 studies to examine effects on (a) standardized foundational skill measures (mean ES = 0.54), (b) nonstandardized foundational skill measures (mean ES = 0.62), (c) standardized language/comprehension measures (mean ES = 0.36), and (d) nonstandardized language/comprehension measures (mean ES = 1.02). There were no differences in effects related to intervention type, instructional group size, grade level, intervention implementer, or the number of intervention hours.
Wansek, J., Vaughn, S., Scammacca, N., Gatlin, B., Walker, M. A., & Capin, P. (2015). Meta-analysis of the effects of tier 2 reading interventions in grades K-3. Educational Psychology Review, 1-26.