Prevalent User Design is most associated with which characteristic?

• A. Current users
• B. Past users who discontinued
• C. New initiators
• D. Randomized assignment

Answer: (A)

Prevalent user design centers on people who are already using the exposure at the start of the study, i.e., current users at baseline. This means the study selects individuals who have continued use up to the point of entering the study, rather than those who are just starting or who have stopped. This focus on ongoing users makes the design most closely associated with current users. It contrasts with including new initiators (those who begin the exposure during follow-up) or past users who discontinued, and it isn’t defined by randomized assignment, which is a feature of many experimental designs. Keep in mind that studying prevalent users can introduce survivor bias, since those who tolerate or benefit from the exposure long enough to remain prevalent may differ from new starters.