Biostatistics & Research · single question
Which study best establishes the TEMPORAL relationship between exposure and disease (i.e., that exposure preceded disease)?
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Correct answer: B. Prospective cohort study
A prospective cohort study follows disease-free participants FORWARD in time, measuring exposure at baseline then observing who develops disease. Since exposure is measured BEFORE disease develops, temporality is clearly established — a key criterion for causation. Retrospective studies cannot establish temporality as clearly.
- A. ❌ Case-control looks backward from disease to exposure — temporal relationship is less clear.
- B. ✅ Prospective cohort — follows participants forward; exposure is measured before disease occurs, establishing temporality.
- C. ❌ Cross-sectional measures exposure and disease at the SAME time — cannot establish temporal sequence.
- D. ❌ Case report is a single patient description — cannot establish temporal relationships at a population level.
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