Biostatistics & Research · single question
Among PRIMARY study designs, which provides the HIGHEST level of clinical evidence?
Show answer and explanation
Correct answer: D. Randomized controlled trial (RCT)
Evidence hierarchy (primary studies): RCT > Cohort > Case-control > Cross-sectional > Case series > Case report > Expert opinion. RCT provides highest primary evidence due to randomization minimizing bias. Systematic reviews/meta-analyses sit at apex but are secondary research.
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