Which of the following is NOT an essential step in critically appraising a cohort study?

• A. Clarify the research question
• B. Assess measurement validity
• C. Assess follow-up adequacy
• D. Require randomization of exposure

Answer: (D)

The main idea being tested is how to critically appraise a cohort study by focusing on aspects that affect its validity and applicability. In a cohort study, you’re observing people with different exposures over time to see who develops the outcome, so key appraisal steps are about clarity of the research question, the accuracy and consistency of measuring exposures and outcomes, and whether follow-up is complete and long enough to capture the outcome.

Requiring randomization of exposure is not part of this process. Randomization is a feature of experimental designs, like randomized controlled trials, where the investigator assigns exposure. In observational cohort studies, exposure is not assigned; participants naturally have different exposure statuses. Therefore, insisting on randomization would be inappropriate for a cohort study and is not a criterion you use when judging its quality. The other steps—clarifying the research question, assessing measurement validity, and assessing follow-up adequacy—are essential for determining how trustworthy and applicable the study findings are.