HORIZONTAL EQUITY: MEASURES IN SEARCH OF A PRINCIPLE

Abstract

Horizontal equity—the command that equals be treated equally—has received increasing attention, particularly in attempts to assess the desirability of tax reform proposals. It is demonstrated that recent attempts to implement horizontal equity are inconsistent with its stated foundations. More thorough examination raises serious doubts as to whether there is any alternative justification of horizontal equity that would support many common applications of the concept. Examples typically offered to motivate support for horizontal equity are shown to resonate with our intuition only because of the concept's congruence (in such cases) with conventional understandings of risk and vertical equity. Many remaining practical uses of horizontal equity are noted.