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

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

Answer: (D)

Dominance means you get more health benefit while spending less. On the cost-effectiveness plane, this happens when the intervention saves cost and improves effect.

With cost differences on the horizontal axis and effect differences on the vertical axis, that win‑win scenario sits in the upper-left quadrant: you are to the left (cost saved) and up (health gains). The other quadrants describe either more cost with more effect, more cost with less effect, or less cost with less effect—none of these are the dominant position.

So, the key idea is: the dominant quadrant is the one where costs go down and outcomes improve. If your axis labeling is reversed in your course, the exact quadrant might look different, but the principle remains the same.