The authors conducted a meta-analysis of 25 years of mathematics interventions for students with mathematics difficulty or disability in grades 4 through 12. A search of the literature yielded 25 studies that met the inclusion criteria. Studies were coded to extract important study information (e.g., participant information, research design, description of treatment and comparison groups) and data needed to calculate Hedges’s g. The authors used robust variance estimation to address dependence resulting from multiple outcomes per study. The robust variance estimation random-effects model estimated a treatment effect of 0.85. After adjusting for small study effects, the final model estimated an underlying, moderate effect of 0.49 with a large amount of unexplained heterogeneity between studies. Studies with more than 15 hours of treatment and those focused on fractions, however, significantly moderated mathematics outcomes. Findings are limited by extreme variability across study estimates, the lack of standardized mathematics measures, and a limited number of studies across 25 years of research.
Stevens, E. A., Rodgers, M. A., & Powell, S. R. (2018). Intensive interventions in mathematics for upper elementary and secondary students: A meta-analysis of research. Remedial and Special Education, 39, 327–340. doi:10.1177/0741932517731887