Biostatistics & Research · single question
Which study design BEST eliminates selection bias and confounding?
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Correct answer: A. Randomized controlled trial
The RCT best controls bias and confounding. Randomization distributes both known and unknown confounders equally between groups.
- A. ✅ CORRECT – Randomization in RCTs is the most effective method to control confounding and eliminate selection bias.
- B. ❌ Cross-sectional studies have temporal ambiguity.
- C. ❌ Case-control studies are prone to recall bias and selection bias.
- D. ❌ Cohort studies cannot randomize; residual confounding remains.
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