# Attributable Risk vs Absolute Risk Reduction

#### gastroguy

##### New Member
Hi,

I am hoping to understand the difference between attributable risk and absolute risk reduction. Mathematically, the two entities seem equivalent, but the formulas for calculating their confidence interval are quite different (https://www2.ccrb.cuhk.edu.hk/stat/confidence interval/CI for relative risk.htm, https://www2.ccrb.cuhk.edu.hk/stat/confidence interval/CI for ratio.htm). I presumed that attributable risk is used in prospective studies in the context of discussing risk ratio, while ARR is used in retrospective studies in the context of discussing odds ratio.

I appreciate your feedback and comment.