Which metric summarizes the additional cost required per unit of health gained when comparing two treatments?

• A. NNT
• B. ICER
• C. ROI
• D. DALY

Answer: (B)

The key idea is measuring value when two treatments differ in both cost and health effect. The metric that sums the extra money you must spend to gain an additional unit of health is the incremental cost-effectiveness ratio. It’s calculated by taking the difference in costs between the two options and dividing that by the difference in their health outcomes (such as QALYs or life-years gained). The result—cost per extra health unit—lets you compare whether the additional benefit is worth the extra price, often against a willingness-to-pay threshold. If the new treatment costs more but provides notably better health, the ICER tells you whether that trade-off is acceptable. If the new option is more effective and less costly, it’s clearly favorable. Alternatives like NNT focus on the number of patients needed to treat for one event and aren’t about cost per health unit; ROI centers on financial return; and DALY is a burden measure, not a cost-effectiveness ratio. In practice, ICER is commonly reported as cost per QALY gained.