Clinical equivalence

A clinical equivalence study is a comparative study that aims to demonstrate that the difference in outcomes between two or more interventions is so small that it is considered clinically unimportant. This is achieved by setting a pre-specified equivalence margin – a range around the reference (comparator) intervention’s outcome within which the new intervention’s outcome must fall to be considered equivalent. Establishing equivalence typically requires two-sided statistical significance testing. This more technical meaning of ‘clinical equivalence’ should not be confused with its more common clinical use, where clinicians may consider treatment options to be equivalent (e.g. in efficacy, safety). While clinical equivalence studies are similar to non-inferiority studies in rationale and design, it is important to note that they are distinct concepts.