Cost-Effectiveness Analysis (CEA)

A cost-effectiveness analysis (CEA) is a method of economic evaluation that compares the additional cost of one health intervention against the additional health benefit it produces, where that benefit is measured in a natural clinical unit specific to the condition being studied — a life-year gained, a stroke averted, a millimetre of mercury of blood pressure reduced — rather than a generic, cross-condition utility measure. CEA is the broad family of economic-evaluation methods that a incremental cost-effectiveness ratio (ICER) is the output of, and it is the umbrella term under which cost-utility analysis (CUA) sits as one specific, QALY-denominated variant.

How a CEA is calculated

CEA = (Cost of intervention A − Cost of intervention B) ÷ (Outcome from intervention A − Outcome from intervention B), producing an ICER expressed as cost per unit of the chosen outcome. The defining methodological choice in any CEA is the outcome measure: unlike cost-utility analysis, which always denominates in QALYs specifically so that unrelated disease areas can be compared on one scale, a CEA’s outcome can be any natural clinical endpoint that is meaningful for the condition under study — cases of disease prevented, symptom-free days gained, successful treatments achieved.

CEA vs. cost-utility analysis vs. cost-benefit analysis

These three related methods are frequently confused with one another because all three compare an intervention’s cost against a health benefit, but they differ in exactly one place — how the benefit side is measured:

• Cost-effectiveness analysis (CEA). Benefit measured in a natural clinical unit specific to the condition (life-years, cases averted, symptom-free days). Cannot be meaningfully compared across different disease areas, because a cost-per-stroke-averted figure and a cost-per-successful-treatment figure are not on the same scale.
• Cost-utility analysis (CUA). A specific, standardised form of CEA that always denominates benefit in QALYs, which blend survival and health-related quality of life into one scale. Because every CUA uses the same QALY denominator, results across completely different interventions — a cancer drug, a hip replacement, a mental-health therapy — become directly comparable. This is why NICE and most HTA bodies require CUA specifically, not CEA generally, as their reference-case method.
• Cost-benefit analysis (CBA). Converts the health benefit itself into a monetary value, so the result is a net dollar figure (benefits minus costs) or a benefit-cost ratio, rather than a cost-per-outcome ratio. CBA can, in principle, answer whether a program is worth doing in absolute terms; CEA and CUA can only ever rank alternatives relative to each other.

Why the distinction matters for a technology appraisal

A submission to NICE, the US nonprofit Institute for Clinical and Economic Review, or an equivalent HTA body is almost always required to use cost-utility analysis specifically, not a generic CEA with a natural-unit outcome — CASRAI’s NICE technology appraisal process guide covers how that QALY-based cost-utility estimate is actually used inside a live appraisal decision, and the current standard for reporting either type of study transparently is covered in CASRAI’s CHEERS 2022 checklist guide.

Frequently asked questions

Is cost-effectiveness analysis the same as cost-utility analysis?

No. Cost-utility analysis is a specific type of cost-effectiveness analysis that always uses QALYs as its outcome measure. A cost-effectiveness analysis that instead reports cost per life-year gained, cost per case averted, or any other natural clinical unit is CEA in the broader sense, not CUA.

Does a CEA always produce a single ICER?

A CEA comparing exactly two alternatives produces one ICER. A CEA comparing three or more alternatives typically requires an incremental analysis across all of them in ascending order of cost, eliminating any option that is dominated (more costly and less effective than another option), before a final ICER table can be presented.

Why not just always use cost-benefit analysis instead?

Converting health outcomes into a monetary value requires an explicit value-of-life or value-of-a-QALY assumption that many health systems and ethics bodies consider contestable. CEA and CUA sidestep that by keeping cost and health outcome in separate units and only ever comparing alternatives relative to each other, which is why they, not CBA, are the dominant methods in health technology assessment.