Evaluating Intervention Effects in Single-Case Research Designs

Single-case research designs have primarily relied on visual analysis for determining treatment effects. However, current foci on evidence-based treatment have given rise to the development of new methods. This article presents descriptions, calculations, strengths and weaknesses, and interpretative guidelines for 5 effect size indices: the percent of nonoverlapping data, the percent of data exceeding the median, improvement rate difference, nonoverlap of all pairs, and Tau-U.