税收累进性测度的改进：方法、比较和应用

提出判断税收累进性的边际效应方法：当总收入基尼系数的税收边际效应大于0时，该税收具有累进性特征；并将税收边际效应作为测度指数。边际效应指数与K指数具有完全相同的符号，不同税种具有可加性，它比K指数更为稳健，且赋予了税收累进性新的经济含义：税收对总收入基尼系数贡献率大于平均税率。同时还着重讨论几种测度税收累进性指数的关系，对各种测度指数进行了实证，发现S指数存在一定程度的缺陷。

Improving Measurement of Tax Progressivity

This paper promotes the marginal effect method that measures tax progressivity using Gini coefficient decamped by sources: a tax system is progressivity as tax revenue marginal effect of before-tax income Gini coefficient is positive, and marginal effect is regarded as measurement of tax progressivity. The marginal effect index has the same sign as K index, and it is more robust than K index, it has additive property and gives tax progressivity a new economic meaning that ratio of tax contribution to Gini coefficient is greater than average tax rate. The relative of several indices of measurement of tax progressivity is discussed and examples of application of these indices are given to confirm their relations, and some flaw of S index is discovered.