Biostatistics & Research · single question
Which of the following study designs would be BEST for evaluating an intervention (e.g., testing a new fluoride treatment)?
Show answer and explanation
Correct answer: C. Randomized controlled trial (RCT)
The randomized controlled trial (RCT) is the gold standard for evaluating interventions. Random assignment to treatment or control minimizes selection bias and confounding. It provides the strongest evidence for cause-and-effect relationships between an intervention and outcome. Cross-sectional studies describe prevalence; case-control studies look at past exposures in disease vs. non-disease groups; ecological studies look at populations, not individuals.
- A. ❌ Ecological studies use population-level data and cannot draw individual-level conclusions (ecological fallacy).
- B. ❌ Cross-sectional surveys measure prevalence at one point in time and are not designed to test interventions.
- C. ✅ CORRECT – The RCT is the best study design for testing interventions due to randomization, which controls for confounding variables.
- D. ❌ Case-control studies identify risk factors for existing disease (retrospective) — not used to test new treatments.
Practice Biostatistics & Research questions Biostatistics & Research study notes