Relative Risk Calculator

TATITIC CALCULATOR Relative Risk A precise tool.
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What is the Relative Risk & How does it work?

Relative risk (RR) is a measure used in epidemiology to compare the probability of an event occurring in an exposed group versus an unexposed group. It quantifies how much more (or less) likely the outcome is among those with the exposure.

To calculate RR you need a 2×2 contingency table that records the number of cases and non‑cases in both exposure categories. The four cell counts are denoted as a, b, c, and d, where a and b belong to the exposed group, and c and d belong to the unexposed group.

The formula combines the two incidence proportions (risk) and expresses their ratio. An RR of 1 indicates no association, >1 suggests increased risk with exposure, and <1 suggests a protective effect.

RR = frac{a/(a+b)}{c/(c+d)}
a = exposed cases, b = exposed non‑cases, c = unexposed cases, d = unexposed non‑cases
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Parameters
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Frequently Asked Questions
What is relative risk?
Relative risk (RR) compares the probability of an event occurring in an exposed group versus an unexposed group.
How do I calculate relative risk?
To calculate RR, you need a 2×2 contingency table with counts of cases and non-cases in both exposure categories.
What are the four cell counts in the contingency table?
The four cell counts are denoted as a, b, c, and d. ‘a’ and ‘b’ belong to the exposed group, while ‘c’ and ‘d’ belong to the unexposed group.
Can relative risk be greater than 1?
Yes, if RR is greater than 1, it indicates that the event is more likely in the exposed group compared to the unexposed group.
What does a relative risk of 1 mean?
A relative risk of 1 means there is no difference in the likelihood of the event between the exposed and unexposed groups.
How do I interpret a relative risk less than 1?
If RR is less than 1, it indicates that the event is less likely to occur in the exposed group compared to the unexposed group.
Can relative risk be negative?
No, relative risk cannot be negative. It is always a non-negative value.

Results are for informational purposes only and do not constitute professional advice.