The use of effect size estimates to complement visual analysis has become increasingly emphasized in single-case research design (SCRD) studies in special education. This review examined trends in SCRD publication and ES reporting practices across three major special education journals (i.e., Journal of Special Education, Exceptional Children, and Remedial and Special Education) from 2001 to 2025. A total of 1969 articles were screened, yielding 194 SCRD intervention studies and 124 SCRD systematic reviews/meta-analyses. Results indicated a sustained increase in the publication of SCRD studies over time, accompanied by a marked rise in ES reporting. Overall, 42.27% (n = 82) of SCRD intervention studies and 55.65% (n = 69) of SCRD systematic reviews reported at least one effect size estimate, with the highest rates observed in the most recent publication period (2001–2025). Across both intervention studies and systematic reviews, Percentage of Nonoverlapping Data and Tau-U were the most frequently reported ES metrics, although reliance on Percentage of Nonoverlapping Data declined over time while use of Tau-U increased. Findings highlight evolving effect size reporting practices and have implications for evidence synthesis and methodological standards in special education research.
Balikci et al. (Sat,) studied this question.