How is absolute risk reduction calculated?

Absolute risk reduction (ARR) is a measure used to determine the effectiveness of a treatment by quantifying how much a treatment reduces the risk of an event occurring compared to a control group. To calculate ARR, you take the event rate in the control group (the percentage of participants experiencing the event without the treatment) and subtract the event rate in the treatment group (the percentage of participants experiencing the event while receiving the treatment).

The formula is structured as follows:

ARR = % risk in control group - % risk in treatment group.

The correct answer reflects this calculation method, providing a clear representation of how much the treatment lowers the risk compared to no treatment. This metric is crucial in clinical decision-making, as it allows healthcare providers to communicate the benefits of a treatment intervention clearly and effectively to patients and other stakeholders. It highlights not just statistical significance but the actual difference in risk that can be expected as a result of the intervention.

Understanding this calculation is imperative for interpreting the effectiveness of interventions in clinical practice, as it helps to make informed decisions regarding patient care and treatment options.