Question: how do you calculate absolute risk difference?
Answer: AR (absolute risk) = the number of events (good or bad) in treated or control groups, divided by the number of people in that group.
ARC = the AR of events in the control group.
ART = the AR of events in the treatment group.
ARR (absolute risk reduction) = ARC – ART.
RR (relative risk) = ART / ARC.