Which term describes a procedure in which one or more parties to the trial are kept unaware of the treatment assignment?

• A. Blinding/Masking
• B. Audit Certificate
• C. Institutional Review Board Approval
• D. Adverse Event

Answer: (A)

Blinding or masking is the process of keeping one or more parties in a trial unaware of which treatment a participant receives. This helps prevent bias from expectations or conversations about the treatment from influencing outcomes, assessments, or reporting. For example, in a double-blind study, neither the participant nor the investigator knows the treatment allocation, so subjective judgments and placebo effects are less likely to skew results.

The other terms don’t fit because an audit certificate isn’t the mechanism for concealing treatment information, institutional review board approval relates to ethical review and participant protections, and an adverse event is any undesirable medical occurrence, not a method for concealing treatment.