Calculate relative risk between an exposed and unexposed group.
Risk ratio compares probabilities directly and is the most intuitive measure. The odds ratio approximates it only when the outcome is rare, diverging substantially for common outcomes. Reporting an odds ratio as though it were a risk ratio overstates the effect whenever the baseline risk is above about 10 per cent.
Risk Ratio
RR = risk in exposed ÷ risk in unexposed
RR = risk in exposed ÷ risk in unexposed Risk ratio compares probabilities directly and is the most intuitive measure. The odds ratio approximates it only when the outcome is rare, diverging substantially for common outcomes.
Reporting an odds ratio as though it were a risk ratio overstates the effect whenever the baseline risk is above about 10 per cent.
This calculator takes 4 inputs: Events in the exposed group, Total in the exposed group, Events in the unexposed group, Total in the unexposed group. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.