Calculate incremental cost-effectiveness ratio, net monetary benefit, and cost-effectiveness frontier from costs, effects, and WTP.
ICER Formula
For a pairwise comparison, this calculator consistently uses the intervention minus comparator orientation:
ΔC = intervention cost − comparator cost
ΔE = intervention effect − comparator effect
ICER = ΔC ÷ ΔE.
Net monetary benefit for strategy j is NMBj = λEj − Cj, and incremental net monetary benefit is INMB = λΔE − ΔC. A zero incremental effect makes the ratio undefined, even though cost dominance and NMB can still be described.
Dominance and the Multi-Strategy Frontier
A strategy is strongly dominated when another entered strategy costs no more and is at least as effective, with one strict improvement. After strong dominance, the calculator iteratively removes extendedly dominated strategies only when the preceding frontier slope is strictly greater than the next slope. Exactly collinear frontier points are retained. Exact cost/effect duplicates are grouped as equivalent entered points.
The output says which option or tied options have the highest expected NMB at the entered threshold. It does not label one option universally cost-effective. A negative threshold is rejected.
Interpretation Requirements
All strategies must be mutually exclusive and use a common population, analytical perspective, time horizon, discounting and base date, price year, currency, and effect unit. Effects must be coded so larger is better. Do not mix proportions with percentage points. Point estimates do not represent parameter uncertainty, model uncertainty, or budget impact, and there is no universal willingness-to-pay threshold.
Decision-support limitation: This arithmetic cannot determine coverage, clinical value, or policy on its own. Use a complete economic evaluation and sensitivity analysis for real decisions.
