Session (CTI)

The concept of opportunity cost — the health foregone elsewhere when a new intervention is funded — has been central to HTA methodology for decades, yet agreement on how to measure and apply it remains elusive. Debates over supply-side cost-effectiveness thresholds have generated important methodological advances, but have also exposed the limits of empirical consensus: the assumptions required to translate marginal productivity estimates into operational thresholds are consequential, and the stakeholders most affected by those thresholds have little structural incentive to converge on any single estimate. In this respect, the problem may be as much political-economic as it is methodological. At the same time, there is a growing need and momentum to move beyond health-sector-only value frameworks. Broader value elements - productivity, informal care, social participation, and cross-sectoral spillovers - now feature prominently in research agendas, HTA discussions, and frameworks such as ISPOR's Whole Health approach. This raises a fundamental tension: a narrow opportunity cost frame, anchored in health budget displacement, cannot fully accommodate these broader dimensions; yet widening the frame to cross-sectoral resource allocation makes the empirical challenge substantially harder, not easier. The risk is that in the pursuit of theoretical completeness, practical tractability is lost. The question this panel will interrogate is therefore not whether opportunity cost matters - it does - but whether the current framing is adequate for the decisions HTA is now being asked to support. Methods for estimating broader value have advanced considerably, and imperfect evidence about broader value is not obviously worse than imperfect evidence about narrow displacement costs. What would it mean, in practice, to implement a broader opportunity cost perspective in HTA - one that takes displacement seriously across sectors without abandoning the principled foundations that make HTA defensible? And who should bear the burden of proof?