The interpretation of relative risk depends on whether the outcome is positive or negative. Which statement best reflects this caveat?

• A. RR direction is the same for all outcomes.
• B. The magnitude of RR changes with outcome prevalence.
• C. If the outcome is positive, RR below 1 means the exposed are less likely to have the positive outcome.
• D. RR cannot be interpreted without confidence intervals.

Answer: (C)

Relative risk compares how often an event occurs in the exposed group versus the unexposed group, so the meaning of RR depends on how the event is defined. If the outcome is positive, a relative risk less than 1 means the exposed group is less likely to experience that positive outcome, i.e., the exposure is associated with a reduced chance of achieving the beneficial event. This is the precise caveat described: the direction of the association depends on whether the event is favorable. If the outcome were negative, the interpretation would shift (RR < 1 would indicate a lower risk of the harm). Confidence intervals matter for precision but don’t change the basic directional interpretation.