The procedures used in a clinical study to ensure that the investigator, subject, or both are unaware of which treatment is being administered. In a single-blind study, either the investigator or the subject does not know the treatment being received and in a double-blind study both the investigator and the subject are unaware of the treatment being received. Triple-blinding refers to the subjects, investigators, and the investigators analyzing the study results (either interim or final) being unaware of the treatment being received.