Which feature is characteristic of a cross-sectional study?

• A. Establishes temporal relationship between exposure and outcome
• B. Randomizes participants
• C. Measures incidence over time
• D. Measures exposure and outcome simultaneously

Answer: (D)

Cross-sectional studies capture a snapshot of a population by measuring both exposure and outcome at a single point in time. This means you assess them simultaneously, which lets you estimate how common the exposure and the outcome are and whether they’re associated. Because data are collected all at once, you can’t determine which came first, so temporal relationships or causality can’t be established. It isn’t about randomizing participants, which is typical of experimental designs, and it doesn’t follow people over time to observe new cases, so incidence isn’t measured. So the feature that fits best is measuring exposure and outcome simultaneously.