Soc Choice Welfare (1987) 4:253-276 Social Choice Welfare © Springer-Verlag 1987 Social Choice in Economic Environments with Dimensional Variation* David Donaldson 1 and John E. Roemer 2 1 Department of Economics, The Universityof British Columbia,997-I873East Mall, Vancouver, B.C., Canada V6T IY2 2 University of California, Davis, CA 95616, USA Received September 16, 1986/Accepted September 28, 1987 Abstract. An argument for "welfarist" social evaluation is presented that replaces the independence axiom with a consistency axiom for social-evaluation functionals in economic environments. This axiom (consistency across dimen- sion or COAD) requires that, if two allocations contain suballocations in common, and if individual utility functions are projected down to the smaller economy where allocations change, then these small allocations must be ranked in the same way that their ancestral allocations were. The basic result is applied to different information environments and a variety of ethical axioms appropriate to economic environments is investigated. 1. Introduction Social-evaluation functionals that are "welfarist" (Sen 1977a, b, 1979, 1984) make social judgments using utility or welfare information alone. They include utilitar- ianism and maximin utility, and rule out the possibility of singling out the status quo for special treatment or providing "merit" goods (independently of whether people actually benefit in utility terms). In a welfarist setting, social priorities such as food for the starving must be justified by their contribution to well-being and cannot be treated as intrinsically valuable a. In standard social choice theory, welfarism is implied by the axioms of un- limited domain, Pareto indifference and independence of irrelevant alternatives (D'Aspremont and Gevers 1977; Hammond 1979; Blackorby et al. 1984). A weaker welfarism that exempts indifferences (strict-ranking welfarism) can be established using weak Pareto instead of Pareto indifference (Sen 1979). * We are indebted to Charles Blackorby,ErwinDiewert, Ed Morey, BillSchworm and John Weymark for helpful discussions, and to the Social Sciences and Humanities Research Council, the Killiam Foundation and the National Science Foundation, for research support. 1 Welfaristsocial-evaluation functionals (at least as defined here) may or may not use utility information that is consistentwith individual preferences(consumersmay be uninformed or irrational). Thus, welfarism is conceptually distinct from the requirement of "consumers' sovereignty".