“no intervention” control

This design is simpler but leaves the study open to placebo effects and bias, because subjects and assessors know who was treated. Blinded assessment of outcomes can reduce that problem.

A control in which no intervention (including a placebo) is used on the subject. In a treatment study, this could also be referred to as a “no treatment” control.

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