Absolute risk reduction is defined as:

Absolute risk reduction is defined as:

• A. The reduction in risk associated with an intervention compared to control
• B. The increase in risk due to exposure
• C. The baseline risk of disease in the population
• D. The relative difference in risk between two groups

Answer: (A)

Absolute risk reduction is the actual decrease in the probability of the outcome when an intervention is used, compared with a control. It’s found by subtracting the event rate in the treatment group from the event rate in the control group, giving a value in percentage points. This tells you how many fewer events occur because of the intervention in the studied population and is the plain, tangible drop in risk you’re looking for. It’s different from relative risk reduction, which expresses the improvement as a proportion of the control risk, and from baseline risk, which is just how common the outcome is without the intervention. ARR also underpins the practical idea of how many people would need to treat to prevent one event (NNT). In short, ARR captures the actual reduction in risk due to the intervention versus control.

Absolute risk reduction is the actual decrease in the probability of the outcome when an intervention is used, compared with a control. It’s found by subtracting the event rate in the treatment group from the event rate in the control group, giving a value in percentage points. This tells you how many fewer events occur because of the intervention in the studied population and is the plain, tangible drop in risk you’re looking for. It’s different from relative risk reduction, which expresses the improvement as a proportion of the control risk, and from baseline risk, which is just how common the outcome is without the intervention. ARR also underpins the practical idea of how many people would need to treat to prevent one event (NNT). In short, ARR captures the actual reduction in risk due to the intervention versus control.