blinded study

A type of clinical trial or research study in which the participants, researchers or both do not know specific information (such as the study group a participant is in) that may influence them or create bias, which could lead to an error in the final results of the study.

If only the participants do not know specific information, it is called as a single-blind study. When neither the participants nor the researchers know specific information, it is called a double-blind study.

Compare with open-label study.