Will the Real Excess Burden Please Stand Up? (Or, Seven Measures in Search of a Concept)

It is well understood that a tax which distorts relative prices generates a welfare cost or "excess burden" in addition to any associated transfer of resources, but there remains considerable controversy and confusion with respect to procedures for measuring this excess burden. The purpose of this paper is to clarify matters concerning what is one of the most basic concepts in welfare economics. We describe and evaluate a number of alternative conceptual experiments which might lie behind an excess burden calculation, showing how these notions can be represented graphically and algebraically and how they can be approximated numerically.