On the principle of equal sacrifice in income taxation

Abstract

In an influential article by Young ( Journal of Economic Theory, 1988, 44, 321–335), it is shown that the traditional equal sacrifice principles in taxation can be justified from a non-utilitarian perspective by proving that equal sacrifice is, in fact, a consequence of more primitive concepts of distributive justice. This result is obtained in a distribution theoretic setting where total revenue to be raised is fixed. The present paper studies the same question in a setting where the basic problem is to determine a tax function without any reference to the total tax revenue (a setting which is familiar from the theory of progressive taxation) and shows that (i) there exists a utility function (which is continuous and strictly increasing) relative to which all agents sacrifice equally if and only if the tax function is incentive preserving; and (ii) any convex (hence progressive) and incentive preserving tax function equalizes sacrifice relative to a utility function which is continuous, strictly increasing and concave.