Which quadrant of the cost-effectiveness plane represents a dominated intervention?

• A. Upper left quadrant (worse outcomes and higher cost).
• B. Lower right quadrant (better outcomes and lower cost).
• C. Lower left quadrant (less costly and less effective).
• D. Upper right quadrant (more costly and more effective).

Answer: (A)

Dominated means there’s another option that is better on both cost and effectiveness. In the cost‑effectiveness plane, the upper left quadrant shows higher cost and worse outcomes compared with the comparator, so that intervention is strictly dominated. There’s no scenario where it’s preferred over alternatives, since you’d be paying more for worse results. By contrast, the lower-right quadrant (better outcomes and lower cost) represents the ideal, where an option dominates. The lower-left quadrant (less costly but less effective) and the upper-right quadrant (more costly and more effective) reflect trade-offs that depend on thresholds for what’s considered worth paying for extra benefit.