Meta-Analyses of Reading Intervention Studies Including Students With Learning Disabilities: A Methodological Review

Abstract

Learning disabilities (LD) may affect a range of academic skills but are most often observed in reading. Researchers and policymakers increasingly recommend addressing reading difficulties encountered by students with LD using evidence-based practices, or interventions validated through multiple, high-quality research studies. A valuable tool in identifying evidence-based practices is the meta-analysis, which entails statistically aggregating the results obtained through primary studies. Specific methods used in meta-analyses have the potential to influence their findings, with ramifications for research and practice. This review assessed the methodological features of the systematic reviews and analytic procedures featured in meta-analyses of reading intervention studies that included students with LD written between 2000 and 2020. Identified articles ( n = 23) suggest that meta-analyses have become more prevalent and transparent over time, notwithstanding issues related to publication bias and the opacity of coding procedures. A discussion of implications follows a description of results.

Prevalence of Research Design in Special Education: A Survey of Peer-Reviewed Journals

“…Notwithstanding the limitations of group designs (e.g., Ioannidis, 2005) and the need for replications to provide evidence of generality (Sidman, 1960), the reliance on single-case designs may raise issues regarding the external validity of interventions used among students with EBD (see WWC, 2020). On the contrary, the predominance of group design in LD journals could result in interventions targeted toward the “average” at-risk student rather than students who require more intense support (King, Wang, et al, 2022).…”

“…Demonstrating an intervention effect across large numbers of individuals in a group design potentially provides a greater indication of what might be probable in practice; in contrast, a single-case design provides an indication of what might be possible for an individual and generally results in a much larger effect size relative to group designs (King, Rodgers, & Lemons, 2022). Researchers have also encountered difficulty comparing or meta-analyzing single-case designs, which prevents the identification of moderators (i.e., variables with the potential to influence intervention effectiveness; King, Wang, et al, 2022).…”