**Instructions:** This calculator computes the Relative Risk for a 2x2 crosstabulation, which measures the ratio of the risk of developing a condition (or disease) for those exposed to a risk factor, versus the the risk of exhibiting the condition for those that are not exposed to the risk factor. Please type the 2x2 table data and also indicate the confidence level required to compute the confidence interval for the Relative Risk (RR)

## More about the *Relative Risk (RR)*

The relative risk (RR) corresponds to ratio of the risk of developing a disease (or condition) for those exposed to a certain risk factor, versus the the risk of developing the disease (or condition) for those not exposed to the risk factor, which is typically used in Cohort Studies.

Let us consider the following 2x2 crosstabulation:

The Relative Risk (RR) of having the developing a disease for those exposed to a risk factor versus those not exposed to the risk factor is computed using the following formula:

\[RR = \frac{a/(a+b)}{c/(c+d)} \]One related concept is the idea of Odds ratios (OR), which correspond to the ratio of two odds. If you are dealing with that, then you can use our Odds Ratio calculator instead.

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