Absolute Risk Reduction Calculator

Formula

To calculate the Absolute Risk Reduction (ARR):

\[ ARR = CER - EER \]

Where:

\(ARR\) is the Absolute Risk Reduction (percentage)
\(CER\) is the Control Event Rate (percentage)
\(EER\) is the Experimental Event Rate (percentage)

Absolute Risk Reduction Definition

An absolute risk reduction is defined as the difference between the percentage rate of a control event and an experimental rate. It represents the decrease in risk of an adverse event due to the intervention being studied, and is often used in clinical trials to evaluate the effectiveness of a treatment.

Example Calculation 1

Let's assume the following values:

Control Event Rate (\(CER\)) = 15%
Experimental Event Rate (\(EER\)) = 10%

Using the formula:

\[ ARR = 15\% - 10\% = 5\% \]

The Absolute Risk Reduction is 5%.

Example Calculation 2

Let's assume the following values:

Control Event Rate (\(CER\)) = 20%
Experimental Event Rate (\(EER\)) = 12%

Using the formula:

\[ ARR = 20\% - 12\% = 8\% \]

The Absolute Risk Reduction is 8%.