Paired design

Paired designs are common in diagnostic studies, where the new test and the comparator are run on the same specimens. They need fewer subjects, but they do not work when one test affects the result of the other.

The application of two or more interventions or diagnostic tests at the same point in time to the same subjects or subject specimens. This design may be not appropriate if the interventions or test interfere with each other.

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