An intervention demonstrates better outcomes at a lower cost compared to another treatment. How is it classified on the cost-effectiveness plane?

• A. Favorable cost-effectiveness
• B. Time horizon may be too short
• C. Dominated
• D. Dominant

Answer: (D)

Getting this right hinges on understanding how the cost-effectiveness plane works. The plane compares an intervention to a comparator by two differences: cost and effectiveness. If the new intervention costs less and produces better outcomes, it sits in the region where cost difference is negative and effectiveness difference is positive. That position is called dominant: the new option outperforms the comparator on both axes, so there’s no tradeoff needed.

So, better outcomes and lower cost means the intervention dominates the comparator. The other labels don’t fit: being favorable or just time-horizon issues don’t describe this dual advantage, and being dominated would mean it’s worse in both cost and effectiveness.