"This paper critically surveys the large and growing literature estimating the elasticity of taxable income with … assumptions this elasticity can be used as a sufficient statistic for efficiency and optimal tax analysis. We discuss what other … parameters should be estimated when the elasticity is not a sufficient statistic. Second, we discuss conceptually the key issues …

responses. The first elasticity (supply side) is the sole real factor limiting optimal top tax rates. The optimal tax system … should be designed to minimize the second elasticity (avoidance) through tax enforcement and tax neutrality across income … forms, in which case the second elasticity becomes irrelevant. The optimal top tax rate increases with the third elasticity …