The inclusion of spill-over effects in economic evaluations

Introduction
Increasingly, welfare economic evaluations are used in the context of the allocation of scarce healthcare resources. Many jurisdictions prescribe their use in the context of reimbursement, funding, and/or pricing of new health technologies, especially pharmaceuticals. The fact that the outcomes of such evaluations can infuence actual allocation decisions in healthcare underlines the importance of a sound methodology and an appropriate decision-making process. Fortunately, in both areas progress has been made over the past decades. However, there remains room for further improvement, for instance in fnding appropriate estimates of monetary values of health, developing broader outcome measures than quality-adjusted life-years (QALYs), fnding appropriate equity (principles to estimate) weights for health outcomes, and estimating health opportunity costs.