A descriptive survey can become a cross-sectional analytic study when which condition is met?

• A. When exposure and outcome are both measured.
• B. When only exposure is measured.
• C. When neither exposure nor outcome is measured.
• D. When the study is descriptive only.

Answer: (A)

Cross-sectional analytic studies rely on data for both exposure and outcome in the same population at a single point in time so you can assess whether there is an association between them. Measuring both exposure and outcome allows calculation of measures of association, such as prevalence ratios or odds ratios, showing how the presence of exposure relates to the presence of the outcome. If only exposure is measured, or if neither is measured, you cannot evaluate the relationship between the two variables, so the study remains descriptive rather than analytic. Likewise, a study described as descriptive only does not examine associations between factors. Therefore, the condition that makes a descriptive survey become a cross-sectional analytic study is measuring both exposure and outcome.