How does Absolute Risk Reduction differ from Relative Risk Reduction?
While both ARR and RRR are used to measure the effectiveness of an intervention, they convey different information. Relative Risk Reduction is the proportion of risk reduced by the intervention, calculated as: RRR = (Event Rate in Control Group - Event Rate in Treatment Group) / Event Rate in Control Group In contrast, ARR provides the actual difference in risk. For example, if the control group has a 10% event rate and the treatment group has a 5% event rate, the RRR would be 50% (because 5% is half of 10%), while the ARR would still be 5%.
