Gini and Optimal Income Taxation by Rank
研究了基于排序的社会福利函数下的非线性所得税问题，利用基尼系数等位置指标权衡规模与不平等，推导出简单直观的税收公式，并发现美国现行税收政策除顶层外接近最优。
We solve the nonlinear income tax program for rank-dependent social welfare functions, expressing the trade-off between size and inequality using the Gini and related families of positional indices. Absent bunching, ranks in the actual and optimal allocations are invariant. Exploiting this feature, we provide new, simple, and intuitive tax formulas for both the quasilinear and additive cases and new comparative static results. Our approach makes insights from optimal taxation more widely accessible. In some of our simulations the actual US tax policy is close to being optimal—except at the top, where optimal rates are much higher than in actuality.