Risk Ratio Calculator

Formula

To calculate the Risk Ratio (RR):

\[ RR = \frac{CI_e}{CI_u} \]

Where:

\(RR\) is the risk ratio
\(CI_e\) is the cumulative incidence in the exposed group
\(CI_u\) is the cumulative incidence in the unexposed group

What is Risk Ratio?

The risk ratio, also known as the relative risk, is a measure used to compare the risk of a certain event occurring in two groups. It is calculated by dividing the cumulative incidence of the event in the exposed group by the cumulative incidence in the unexposed group[^1^].

Example Calculation 1

Let's assume the following values:

Exposed Group - Positive Outcome = 50
Exposed Group - Total = 200
Unexposed Group - Positive Outcome = 30
Unexposed Group - Total = 300

Using the formula:

\[ RR = \frac{50/200}{30/300} = \frac{0.25}{0.10} = 2.50 \]

The risk ratio is 2.50.

Example Calculation 2

Let's assume the following values:

Exposed Group - Positive Outcome = 70
Exposed Group - Total = 350
Unexposed Group - Positive Outcome = 20
Unexposed Group - Total = 250

Using the formula:

\[ RR = \frac{70/350}{20/250} = \frac{0.20}{0.08} = 2.50 \]

The risk ratio is 2.50.