Paired-samples tests of equivalence

Equivalence tests are used when the objective is to find that two or more groups are nearly equivalent on some outcome, such that any difference is inconsequential. Equivalence tests are available for several research designs, however, paired samples equivalence tests that are accessible and relevant to the research performed by psychologists have been understudied. This study evaluated parametric and nonparametric two one-sided paired-samples equivalence tests and a standardized paired-samples equivalence test developed by Wellek (2003). The two one-sided procedures had better Type I error control and greater power than Wellek’s test, with the nonparametric procedure having increased power with non normal distributions.