Statistical Analysis
Absolute Risk Reduction
What is Absolute Risk Reduction?
Absolute risk reduction (also called risk difference) is the absolute difference in outcomes between one group (usually the control group) and the group receiving treatment.
Absolute Risk Reduction Formula:
Absolute Risk Reduction (AAR) = CER (Control Event Rate) – EER (Experimental Event Rate)
AAR= 3.0% - 1.9% = 1.1%
Interpretation of Absolute Risk Reduction:
The percentage tells you how much the risk of something happening decreases if a certain intervention happens.
If there is a 100 patient in group A (placebo group) and a 100 patient in group B (Lipitor group) only 1 person out of 100 will be helped in group B.