What defines an interventional study?

Correct answer: A. Experimental

• A. Correct. Interventional (experimental) studies actively assign/apply an intervention to participants and observe outcomes (e.g., a clinical trial).
• B. A cohort study is observational — researchers follow groups based on exposure status without assigning an intervention.
• C. A case-control study is observational, comparing those with and without a disease retrospectively for exposures.
• D. A cross-sectional study is observational, assessing exposure and outcome at a single point in time.