The attributable risk is an additional means of comparing both groups. It’s the incidence of disease in the exposed group that can be attributed to the exposure. In epidemiological studies, the number needed to harm is often abbreviated as NNH. It’s the inverse of the attributable risk, that is, 1 divided by the attributable risk.

Outline:
00:00 - Introduction
01:08 - Attributable risk
01:52 - Attributable risk percent
02:22 - Number Needed to Harm (NNH)
03:11 - Number Needed to Treat (NNT)
04:43 - Summary
05:26 - Quiz