Absolute Risk Reduction (ARR)

Absolute Risk Reduction (ARR) quantifies the decrease in risk of a negative outcome resulting from exposure to a specific treatment or intervention, compared to a control group without such exposure. This measure is integral to the evaluation of treatment efficacy in clinical trials and health economics, particularly for assessing the incremental benefits in cost-effectiveness studies, as demonstrated in the Incremental Cost-Effectiveness Ratio (ICER). ARR not only offers a direct measure of a treatment’s protective benefits but also corresponds to the Number Needed to Treat (NNT), which indicates how many patients require a specific intervention to prevent one adverse event. This relationship underscores ARR’s crucial role in evidence-based medicine, providing a clear, quantifiable metric that aids healthcare providers and policymakers in making informed decisions regarding the efficacy and economic viability of medical interventions. Additionally, ARR’s utility in public health and clinical research facilitates the comparison of treatment effectiveness across studies, helping prioritize interventions that deliver significant health improvements and cost efficiency. Understanding ARR’s impact also enhances patient communication, enabling individuals to make well-informed healthcare choices based on solid risk reduction data.