Box 15.1.b: Types of full economic evaluation
All types of full economic evaluation compare the costs (resource use) associated with one or more alternative interventions (e.g. intervention X versus comparator Y) with their consequences (outcomes, effects). All types value resources in the same way (i.e. by applying unit costs to measured units of resource use). The types differ primarily in the way they itemize and value effects. These differences reflect the different aims and viewpoints of different decision problems (or economic questions).
Cost-effectiveness analysis (CEA): the effects of an intervention (and its comparators) are measured in identical units of outcome (e.g. mortality, myocardial infarctions, lung function, weight, bleeds, secondary infections, revisional surgeries). Alternative interventions are compared in terms of ‘cost per unit of effect’.
Cost-utility analysis (CUA): when alternative interventions produce different levels of effect in terms of both quantity and quality of life (or different effects), the effects may be expressed in utilities. Utilities are measures which comprise both length of life and subjective levels of well-being. The best known utility measure is the quality-adjusted life year, or QALY. Alternative interventions are compared in terms of cost per unit of utility gained (e.g. cost per QALY).
Cost-benefit analysis (CBA): when both resource inputs and effects of alternative interventions are expressed in monetary units, so that they compare directly and across programmes within the healthcare system, or with programmes outside health care (e.g. healthcare intervention vs. criminal justice intervention).