What is the formula for calculating absolute risk?

Absolute risk is calculated by determining the number of events that occur in a specific group and dividing that number by the total number of individuals in that same group. This approach gives a clear measure of the risk associated with a particular outcome within a defined population.

In the context of the choices provided, the correct response indicates that to understand the absolute risk, one must focus exclusively on the number of events occurring either in the treatment or the control group, divided by the total number of individuals in that particular group. This allows health professionals to assess the direct impact of an intervention or condition on a population.

Other options do not provide an accurate calculation for absolute risk. For example, dividing events by the number of people in the control or treatment group separately, without considering the group to which the events pertain, might lead to an incomplete understanding of the intervention’s effect. A similar consideration applies to options that suggest summing events from both groups, which could obscure the treatment's specific effects.