In cross-sectional study analysis, which statement best describes the typical comparison?

• A. Incidence among exposed and unexposed groups.
• B. Prevalence among exposed and unexposed groups.
• C. Outcome prevalence in exposed vs unexposed.
• D. Cumulative incidence over time between exposure groups.

Answer: (C)

In a cross-sectional study, you capture exposure and outcome at a single point in time, so you’re looking at how common the outcome is in different exposure groups. The meaningful comparison is the outcome prevalence in those who are exposed versus those who are not exposed. Since there’s no follow-up, you can’t determine incidence (new cases over time) or cumulative incidence, which require observing people over a period. For example, you’d compare how many people with a given exposure currently have the outcome, not how many develop it over time.