Table 1.

Differences in the Approach of Randomized Controlled Trial and Economic Evaluation.

Characteristic	Approaches for undertaking economic evaluation
	RCT	Decision model
Focus of assessment	Internal validity	External validity
Time horizon	Usually short – enough to estimate proximal clinical endpoints	Usually long – to comprehensively estimate downstream costs and consequences
Measure of outcome	Usually proximal clinical endpoint, eg. reduction in blood pressure	Utility-based measure such as quality-adjusted life year (QALY)
Number of comparators	Limited	No limitation

RCT: randomized controlled trial, QALY: quality-adjusted life year.