Non-inferiority study

The non-inferiority margin has to be set before the study and justified both clinically and statistically, since a wide margin can make a weaker device look acceptable. Showing non-inferiority does not show that the device is better.

Study designed to demonstrate that the safety or effectiveness of an investigational device is not worse than the comparator by more than a specified margin.

FDA guidance: Design Considerations for Pivotal Clinical Investigations for Medical Devices (November 2013), Section 11, Glossary