Relative Risk

Question 1

Relative risk (RR)

Answer 1

RR = EER / CER

EER = rate at which events occur in the experimental group
CER = rate at which events occur in the control group

Question 2

Relative risk reduction

Answer 2

Relative risk reduction:

The relative risk reduction (RRR) is the proportion by which the intervention reduces the event rate.

Relative risk reduction (RRR) or relative risk increase (RRI) is calculated by dividing the absolute risk reduction (risk difference) by the control event rate

RRR = ARR / CER
RRR = (CER - EER) / CER

Using the above data

RRI = (CER - EER) / CER