Relative Risk
In statistics and mathematical epidemiology, relative risk (RR) is the risk of an event (or of developing a disease) relative to exposure. Relative risk is a ratio of the probability of the event occurring in the exposed group versus a non-exposed group.
| Risk | Disease status | |
|---|---|---|
| Present | Absent | |
| Smoker | ||
| Non-smoker | ||
Consider an example where the probability of developing lung cancer among smokers was 20% and among non-smokers 1%. This situation is expressed in the 2 × 2 table to the right.
Here, a = 20, b = 80, c = 1, and d = 99. Then the relative risk of cancer associated with smoking would be
Smokers would be twenty times as likely as non-smokers to develop lung cancer.
Another term for the relative risk is the risk ratio because it is the ratio of the risk in the exposed divided by the risk in the unexposed.
Read more about Relative Risk: Statistical Use and Meaning, Worked Example, See Also
Famous quotes containing the words relative and/or risk:
“Man may have his opinion as to the relative importance of feeding his body and nourishing his soul, but he is allowed by Nature to have no opinion whatever as to the need for feeding the body before the soul can think of anything but the body’s hunger.”
—George Bernard Shaw (1856–1950)
“The Englishman’s strong point is his vigorous insularity; that of the American his power of adaptation. Each of these attitudes has its perils. The Englishman stands firmly on his feet, but he who merely does this never advances. The American’s disposition is to step forward even at the risk of a fall.”
—Thomas Wentworth Higginson (1823–1911)