Relative risk compares which probabilities?

Relative risk is a measure used in epidemiology to determine the likelihood of an event occurring in two different groups. Specifically, it compares the probability of an event happening in the group that has been exposed to a certain factor or intervention to the probability of the same event occurring in a group that has not been exposed.

Thus, the correct answer focuses on the probability of the event in those who have been exposed to the risk factor versus those who have not. This comparison allows researchers to quantify the strength of the association between exposure and the outcome. In this way, relative risk helps in understanding if exposure increases, decreases, or has no effect on the risk for the event.

The other possible choices address various aspects of risk assessment but do not accurately reflect the definition of relative risk. For instance, one option suggests comparing the event occurrence rate in all participants, which does not distinguish between exposed and unexposed groups. Another focuses on the general population risk compared to the exposed population, which is broader and not aligned with the specific comparative nature of relative risk.