MCAT® ExamPsychological, Social, and Biological Foundations of BehaviorMedium
A clinical trial investigates the efficacy of a new antidepressant. Participants are randomly assigned to either a treatment group receiving the new drug or a control group receiving a placebo. To avoid bias, neither the participants nor the researchers administering the drug know who is receiving which treatment. However, the head researcher, who designed the study and will analyze the data, is aware of the group assignments. This study design is an example of what type of experimental control?
- ATriple-blind study
- BDouble-blind study
- CSingle-blind study
- DOpen-label study
Show answer & explanationAnswer & explanation
Correct answer: C. Single-blind study
In a single-blind study, either the participants or the researchers (but not both) are unaware of the treatment assignments. Here, participants and administering researchers are blind, but the head researcher is not.
Why the other options are wrong
- A. A triple-blind study extends blinding to the data analyst as well, ensuring that no one involved in the participant interaction or data interpretation knows the group assignments.
- B. A double-blind study requires both the participants and the researchers administering the treatment to be unaware of the treatment assignments.
- D. An open-label study is one where both the participants and the researchers know which treatment is being administered, which is the opposite of blinding.
Blinding in Research
A procedure in clinical trials and research studies where one or more parties involved in the study (participants, researchers, data analysts) are kept unaware of the treatment assignments to prevent bias.
- Reduces placebo effect and experimenter bias.
- Single-blind: one party unaware.
- Double-blind: two parties unaware (participant and researcher administering treatment).
- Triple-blind: all three parties unaware (participant, researcher, data analyst).
Memory trick: Blinding: Blocking Bias, Better Beliefs.