Open-label trial
An open-label trial, or open trial, is a type of clinical trial in which both the researchers and participants know which treatment is being administered.[1][2] This contrasts with single blind and double blind experimental designs, where participants are not aware of what treatment they are receiving (researchers are also unaware in a double blind trial).
Open-label trials may be appropriate for comparing two very similar treatments to determine which is most effective. An open-label trial may be unavoidable under some circumstances, such as comparing the effectiveness of a medication to intensive physical therapy sessions.
An open-label trial may still be randomized. Open-label trials may also be uncontrolled (i.e. without a placebo group), with all participants receiving the same treatment.