Absolute Risk Reduction Calculator

ARR is used in studies to define the absolute difference in outcomes between one group, the treatment receiving one and the other group, the control one, which offers information about by how much the risk of the studied adverse outcome decreases if a certain treatment or intervention takes place.

• ARR (%) = (ARC – ART) x 100 (if ARC and ART expressed as decimals)
• ARR (%) = (ARC – ART) (if ARC and ART expressed as percentage)

Where:

• ARC = Number of events in control group / Number of people in control group
• ART = Number of events in treatment group / Number of people in treatment group

Jump to:

1. Absolute Risk Reduction Calculator

2. Determining Absolute Risk Reduction

3. References

Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.