Masking, or blinding, is a method used in clinical trials to prevent bias by ensuring that participants, healthcare providers, or researchers do not know which treatment or intervention participants are receiving.

There are different levels of blinding:

• Single-blind: Only the participants are unaware of the treatment they are receiving.
• Double-blind: Both the participants and the researchers are unaware of the treatment assignments.
• Triple-blind: Participants, researchers, and those analyzing the data are all blinded.