Using statistical equivalence testing in clinical biofeedback research

The technique of statistical equivalence testing is described and recommended for use in clinical biofeedback research. Equivalence testing is valuable in aiding the interpretation of negative results or statistically significant results where effects are small in clinical terms. The method is also useful for establishing the similarity of treatment groups at baseline or for showing that the effect of a potentially confounding variable is tolerably small. Finally, equivalence testing is recommended as a method for documenting the equivalence of biofeedback therapy to proven conventional medical therapies in clinical equivalence trials. Examples, drawn from published literature, are provided.