Abstract
This study compared visual analyses with five alternative methods for assessing the magnitude of effect with single subject designs. Each method was successful in detecting intervention effect. When rank ordered, each method was consistent in identifying the participants with the largest effect. We recommend the use of the standard mean difference (SMDall) formula and we believe the use of a regression equation for calculating effect size in single subject data should be avoided.
Acknowledgements
Preparation of this manuscript was supported in part by the Office of Special Education Programs Grant #H324D000068 to Dr. Melissa Olive. However, the opinions expressed herein do not necessarily reflect the position or policy of OSEP, and no official endorsement by the department should be inferred. The authors would like to thank Michael Krezmien for his assistance on earlier drafts of this paper. The authors would also like to thank Dr. Robin McWilliam for his helpful comments related to this analysis. The authors would also like to thank Brian, Dante, Seth, Quincy, Tom, and Reese as well as their parents and teachers for their participation in this project.