Which term is used to describe a method where a participant or investigator is unaware of the treatment assignment?

• A. Blinding/Masking
• B. Adverse Event
• C. Audit Certificate
• D. Adverse Drug Reaction

Answer: (A)

Blinding, or masking, is a technique used in trials to prevent bias by keeping participants and/or researchers unaware of which treatment a participant receives. This helps ensure that expectations or beliefs don’t influence how outcomes are reported or assessed. In a single-blind setup, the participant doesn’t know the assignment; in a double-blind setup, both the participant and the investigator assessing outcomes are unaware. The other terms refer to safety events or administrative documents, not to concealing treatment allocation.