Biostatistics & Research · single question
What type of study is a Randomized Clinical Trial (RCT)?
Show answer and explanation
Correct answer: D. Experimental Study
Experimental Study (D) — an RCT is the gold standard experimental study design. Participants are randomly assigned to intervention or control groups, making it the most powerful study for establishing causality.
Evidence hierarchy (highest to lowest):
1. Systematic Review / Meta-analysis
2. Randomized Clinical Trial (RCT) — experimental
3. Cohort Study — observational, prospective
4. Case-Control Study — observational, retrospective
5. Cross-Sectional / Survey — observational, one time point
6. Case Series / Case Report
7. Expert Opinion
• Surveys and Cross-sectional studies describe prevalence at one point.
• Case-Control looks backward from disease to exposure.
• Only experimental designs (RCTs) truly establish cause and effect through randomization.
Evidence hierarchy (highest to lowest):
1. Systematic Review / Meta-analysis
2. Randomized Clinical Trial (RCT) — experimental
3. Cohort Study — observational, prospective
4. Case-Control Study — observational, retrospective
5. Cross-Sectional / Survey — observational, one time point
6. Case Series / Case Report
7. Expert Opinion
• Surveys and Cross-sectional studies describe prevalence at one point.
• Case-Control looks backward from disease to exposure.
• Only experimental designs (RCTs) truly establish cause and effect through randomization.
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