Clinical equivalence.

When the classical approach of testing the null hypothesis of equality is used and the results are not statistically significant, formal conclusions regarding the "closeness" of the treatments cannot be drawn. When the purpose of the investigation is to exhibit "closeness," misinterpretations may result in inappropriate, or even incorrect, conclusions. Here methodology for use when the goal is to exhibit the equivalence (noninferiority) of the treatments is discussed. The techniques allow direct conclusions to be drawn regarding the equivalence of the treatments. A review is presented.