This article examines the pattern of family-size tax reductions implied by a concern for horizontal equity. Conditions are derived for a falling or rising pattern of reductions with respect to income and for the pattern of marginal reductions at a given income level. The required pattern is systematically related to assumptions about the variations in needs, with family size and the desired progressivity of the tax system. The case in which economies of scale vary with the level of income is singled out and it is shown that previous treatments of this case have been inadequate. Based on this analysis, the adequacy of reductions in the Israeli tax structure is examined.
