A d-statistic for single-case designs that is equivalent to the usual between-groups d-statistics
We describe a standardised mean difference statistic (d) for single-case designs that is equivalent to the usual d in between-groups experiments. We show how it can be used to summarise treatment effects over cases within a study, to do power analyses in planning new studies and grant proposals, and to meta-analyse effects across studies of the same question. We discuss limitations of this d-statistic, and possible remedies to them. Even so, this d-statistic is better founded statistically than other effect size measures for single-case design, and unlike many general linear model approaches such as multilevel modelling or generalised additive models, it produces a standardised effect size that can be integrated over studies with different outcome measures. SPSS macros for both effect size computation and power analysis are available.
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@article{shadish2013,
author = {Shadish, William R. and Hedges, Larry V. and Pustejovsky,
James E. and Boyajian, Jonathan G. and Sullivan, Kristynn J. and
Andrade, Alma and Barrientos, Jeannette},
title = {A d-Statistic for Single-Case Designs That Is Equivalent to
the Usual Between-Groups d-Statistics},
journal = {Neuropsychological Rehabilitation},
volume = {24},
number = {3-4},
pages = {528-553},
date = {2013-07-18},
url = {https://doi.org/10.1080/09602011.2013.819021},
doi = {10.1016/j.jsp.2018.02.003},
langid = {en}
}