MCAT® ExamCritical Analysis and Reasoning SkillsEasy
A medical researcher is conducting a study to evaluate the effectiveness of a new pain medication. To ensure the results are unbiased, neither the patients nor the administering nurses know who is receiving the actual drug and who is receiving a placebo. This experimental design is an example of which of the following?
- ADouble-Blind Study
- BCross-Sectional Study
- CSingle-Blind Study
- DRandomized Control Trial
Show answer & explanationAnswer & explanation
Correct answer: A. Double-Blind Study
A double-blind study is an experimental procedure in which neither the participants nor the researchers (or those administering the treatment) know who is in the experimental group and who is in the control group. This helps prevent bias from both participant expectations and researcher influence.
Why the other options are wrong
- B. A cross-sectional study analyzes data from a population at a specific point in time, rather than tracking changes over time or evaluating interventions. (Incorrect)
- C. A single-blind study involves only one party (usually the participants) being unaware of the treatment assignment. (Incorrect)
- D. A randomized control trial is a broader category of study design that includes randomization and a control group, but does not specifically address the blinding aspect described. (Incorrect)
Double-Blind Study
An experimental procedure where neither the participants nor the researchers administering the treatment know who receives the treatment versus the placebo.
- Minimizes bias from participant expectations (placebo effect).
- Minimizes bias from researcher expectations (observer bias).
- Considered the 'gold standard' for clinical trials.
Memory trick: Blinding protects the study's vision from bias.