Which statement best describes a cross-sectional study?

• A. Follow-up occurs over months to years
• B. Data are collected at a single point in time and all subjects are tested around the same time
• C. Exposure is manipulated by the researcher
• D. It tests causal relationships

Answer: (B)

A cross-sectional study provides a snapshot of a population at a single point in time. It measures both exposure and outcome once, with data collected around the same time, which is ideal for estimating prevalence and examining associations without tracking people over time. Because everything is assessed at one moment, temporality isn’t established, so you can’t infer causation from these data. Following subjects over months or years describes a longitudinal approach, not cross-sectional. Manipulating exposure is an experimental design, not a cross-sectional study, and while cross-sectional analyses can reveal associations, they do not prove causal relationships.