MARK VERSUS LUKE? DECISION MAKING WITH MULTIPLE OBJECTIVES AND MULTIPLE CONSTRAINTS
Karl Claxton, PhD, MSc, BA, University of York, York, United Kingdom, Mark Sculpher, PhD, University of York, York, United Kingdom, and Anthony J. Culyer, Institute for Work & Health, Toronto, ON, Canada.
Purpose: To demonstrate that a social decision making approach to evaluation can be generalised to interventions which have multiple objectives and impact on multiple constraints within and beyond the health sector. Background: The UK National Institute for Health and Clinical Excellence (NICE) has been given additional responsibilities for issuing guidance on public health interventions and national policies which will have an impact across public sector budgets and the wider economy. This poses the question whether the existing approach to the evaluation of health technologies within the health sector is sufficient to inform decisions across budget holders with multiple objectives and constraints. Methods: The arguments put forward as to whether a social decision making or ‘welfarist' approach to evaluation will be sufficient are examined. These include the existence of broader outcomes than health (e.g crime and education), multiple budget holders, and external effects on the wider economy (e.g productivity). We identify the generalisations of existing decision rules which are required. Results: Current decision rules in CEA are based on maximising a single objective subject to a single exogenous budget constraint whereas a welfarist analysis regards budgets to be endogenous. Both fail to fully address the allocation problem posed by public health interventions. We demonstrate that a mathematical programming solution to this problem is possible but the information requirements make it impractical. Instead we propose a simple compensation test for interventions with multiple and cross sectoral effects. However, rather than compensation based on individual preferences, it should be based on the net benefits falling on different sectors. The valuation of outcomes is based on the shadow prices of the existing budget constraints which are implicit in existing public expenditure and its allocation across different sectors. We show that it is not necessary to pay compensation for each decision if the net compensation required is accounted for over a budget period and informs the marginal changes in subsequent allocations between sectors. Conclusions: A generalisation of decision rules to multiple sectors is required based on compensation valued in a way which is consistent with the existing allocation between the public sector(s) and the wider economy. A ‘welfarist' societal perspective is not sufficient; rather, a multiple perspective evaluation which accounts for costs and effects falling on each sector is required.