Many of the analytical models commonly used in educational research often aim to maximize explained variance and identify variable importance within models. These models are useful for understanding general ideas and trends, but give limited insight into the individuals within said models. Data envelopment analysis (DEA), is a method rooted in…

Presents use of the effect size as a descriptive statistic for single-subject research. Discusses the way in which effect sizes augment interpretation of results, and reviews four types of treatment effects with case studies. An appendix includes a sample computer program for computing effect sizes. (SLD)