1Economic evaluation is the umbrella for methods that make trade-offs between health interventions explicit.

2You've identified an intervention that works. The harder question is, is it a good use of resources? Health budgets are finite, and money spent on Intervention A is money not available for Intervention B. An intervention might save lives but cost so much that we could save more lives by funding something else.

3A cost analysis asks what an intervention costs to deliver. Cost-effectiveness analysis divides costs by a natural health outcome, like infections averted or lives saved, to give a cost per unit of effect. Cost-utility analysis uses a generic metric like DALYs or QALYs, which lets us compare interventions targeting different diseases. And cost-benefit analysis monetizes everything, including health benefits, so we can compare across sectors.

4In global health, cost-effectiveness and cost-utility analysis do most of the work, and the line between them blurs in practice. Many studies report cost per DALY averted and call themselves cost-effectiveness analyses. The summary metric is the incremental cost-effectiveness ratio: the difference in cost between two options divided by the difference in effect. Economic evaluations come back in depth in the policy chapter, with worked examples, threshold discussions, and the ingredients method for getting the cost side right.