Cost-effectiveness plane.
The difference in QALYs between intervention A and comparator O is represented on the horizontal axis, and the difference in cost on the vertical axis. The slope of the line between intervention A and comparator O is the incremental cost-effectiveness ratio (ICER). If A is located in quadrants II or IV, intervention A is dominant (more effective and less costly than comparator O), in quadrant IV, intervention A is less effective and more costly than O. In quadrants I intervention A is more effective but more costly and in III less effective and less costly. The choice will depend on the cost-effectiveness threshold that represents the maximum amount the decision-maker is willing to pay for a unit of effectiveness. Interventions that fall below the cost-effective threshold would be deemed cost-effective.