Cost-Benefit Analysis and Social Welfare Functions

Abstract

This chapter describes and compares the two most important policy-analysis methodologies in economics: cost-benefit analysis (CBA) and the social-welfare-function (SWF) framework. Both approaches are consequentialist and welfarist; both are typically combined with a preference-based view of well-being. Despite these similarities, the two methodologies differ in significant ways. CBA translates well-being impacts into monetary equivalents, and ranks outcomes according to the sum total of monetary equivalents. By contrast, the SWF framework relies upon an interpersonally comparable measure of well-being. Each possible outcome is mapped onto a list (vector) of these well-being numbers, one for each person in the population; the ranking of outcomes, then, is driven by some rule (the SWF) for ranking these well-being vectors. The utilitarian SWF and the prioritarian family of SWFs (each corresponding to well-developed positions in moral philosophy) are especially plausible. The case for using CBA rather than one of these SWFs is weak—or so the chapter argues.