What is the formula for relative risk reduction?

Relative risk reduction is a measure used to express the effectiveness of an intervention in reducing the risk of a certain event occurring in a treated group compared to a control group. It is calculated using the absolute risk of the event occurring in the control group versus the absolute risk in the treatment group.

The formula for relative risk reduction is the difference between the absolute risk of the control group (ARC) and the absolute risk of the treatment group (ART), divided by the absolute risk in the control group. This can be expressed mathematically as:

Relative Risk Reduction = (ARC - ART) / ARC

This formula reflects how much risk is reduced in the treatment group compared to the control group, providing a useful perspective on the effectiveness of a treatment. It is important for evaluating the public health impact of therapies or interventions.

In this context, the option that presents this formula accurately is the correct one. The other options do not provide the correct calculation for relative risk reduction, either altering the relationship of risk or the mathematical operations involved.