In this Briefing, five leading European experts in health economics provide a comprehensive international review of changes in health economic evaluation and the reasons for them.  The authors express concern that the basis for health care decision making today has evolved away from the societal perspective of cost benefit analysis to the payer perspective of cost-effectiveness analysis.  Most voluntary and mandatory guidelines for evaluating medical innovation now encourage or require this narrower, budget-based payer perspective.  As a result, they argue, decisions often are suboptimal, for both health care and economies as a whole.