In disease study designs, retrospective classification refers to analyzing data from past events; which option corresponds to retrospective?

• A. Retrospective
• B. Concurrent
• C. Cross-sectional
• D. Prospective

Answer: (A)

Retrospective design means you analyze data after the events have already occurred. In this approach, you start with the outcome or disease status and look back in time to see what exposures or risk factors these individuals had, often using existing records or asking about past experiences. This is why the option that fits is the one described as looking back at past events and data.

In contrast, prospective studies begin with exposure or risk factors and then follow people forward in time to see who develops the outcome, which is the opposite direction of time flow. Concurrent or cross-sectional designs collect exposure and outcome data at roughly the same time, providing a snapshot rather than a time-sequenced view, so they don’t capture the temporal relationship in the same way retrospective or prospective designs do.

Understanding this helps you recognize why retrospective is the correct match for analyzing past events to determine past exposures.