Biostatistics & Research · single question
What is the best study method to avoid bias?
Show answer and explanation
Correct answer: A. Randomization
Randomization (randomly assigning subjects to groups) is the most powerful tool for minimizing selection bias and balancing both known and unknown confounding variables between study groups — it's the defining feature that makes randomized controlled trials the strongest design for establishing causality.
- A. Case reports are the lowest level of evidence with highest risk of bias.
- B. Correct. Randomization (random allocation of participants to groups) is the most powerful method to control for both known and UNKNOWN confounding variables, thereby minimizing selection bias and confounding bias. It is the hallmark of the RCT.
- C. Cohort design has lower bias risk than case-control but is still observational and cannot eliminate confounding as effectively as randomization.
- D. Observational designs cannot eliminate selection bias or confounding.
Practice Biostatistics & Research questions Biostatistics & Research study notes