Effect size estimation for one-sample multiple-choice-type data: Design, analysis, and meta-analysis.

This article proposes a standard, easy-to-interpret effect size estimate for one-sample research. The proportion index (*•) shows the hit rate on a scale on which .50 is always the null value regardless of the number of equally likely choices. The index r is useful in the design of one-sample research because it can guide the best choice of number of response alternatives. Significance tests and confidence limits are readily computed. For meta-analyses of one-sample studies, tests of heterogeneity of a set of TS and contrasts among them are described.