The type of study where both researchers and study participants are unaware of who is getting the control and who is getting the experimental food or pill is called a ________________- experiment.

The type of study where both researchers and study participants are unaware of who is getting the control and who is getting the experimental food or pill is called a ________________- experiment.

• A. Single-blind
• B. Open-label
• C. Double-blind
• D. Cross-over

Answer: (C)

Double-blind experiments conceal the treatment allocation from both participants and investigators, which prevents expectations from shaping how people respond and how outcomes are assessed. This level of concealment reduces bias from either side, making the comparison between the experimental and control groups more reliable, especially when outcomes could be influenced by perception or observer judgment. If only participants are unaware, that’s single-blind; if everyone knows, that’s open-label; cross-over refers to the order of receiving treatments rather than to blinding itself.

Double-blind experiments conceal the treatment allocation from both participants and investigators, which prevents expectations from shaping how people respond and how outcomes are assessed. This level of concealment reduces bias from either side, making the comparison between the experimental and control groups more reliable, especially when outcomes could be influenced by perception or observer judgment. If only participants are unaware, that’s single-blind; if everyone knows, that’s open-label; cross-over refers to the order of receiving treatments rather than to blinding itself.