Relative Risk Calculator
Calculate the relative risk (risk ratio) comparing event rates between exposed and unexposed groups. Also computes absolute risk difference, NNT, and 95% confidence interval.
Relative risk compares the probability of an event between two groups.
Formula: RR = [a/(a+b)] / [c/(c+d)]
Interpretation:
- RR = 1: Equal risk in both groups
- RR > 1: Higher risk in exposed group
- RR < 1: Lower risk in exposed group
Absolute Risk Difference (ARD): ARD = risk_exposed - risk_unexposed
Number Needed to Treat (NNT): NNT = 1 / |ARD|
NNT tells you how many people need to be treated for one additional person to benefit (or be harmed).