A dollar is a dollar is a dollar - or is it?

It is normally stated that an economic evaluation should take the societal perspective and that this implies the incorporation of all costs and effects, regardless of where these occur. Nevertheless, this broad perspective may be in conflict with the narrower perspective of the health-care decision-makers we are usually trying to aid. In this article, it is argued that not all costs have to be considered equally important for health-care decision-making and that there is a discrepancy between the economically preferred societal perspective and the aim of aiding health-care decision-makers. This is related to the concept of local rationality. Three reasons why some costs may be considered more important for health-care decision-makers than others are: 1) relevance; 2) equity; and 3) responsibility. We suggest that it may be useful to adopt a two-perspective approach as a standard, presenting one cost-effectiveness ratio following a strict health-care perspective and one following the common societal perspective. The health-care perspective may assist the health-care policymaker better in achieving health-care goals, while the societal perspective indicates whether the local rationality of the narrow health-care perspective is also in line with societal optimality. More research on actual decisions should provide more insight into the relative weights attached to different types of costs.