The structure of the Italian personal income tax has undergone several important changes since its introduction in 1974, following a path similar to those in other advanced economies. These modifications have affected its redistributive impact in ways that a priori are not easily identifiable, since they have often moved in divergent directions. The aim of this paper is to study how the redistributive effect (i.e. the ability of the tax to reduce inequality in post-tax incomes) and progressivity (i.e. the rate at which tax incidence increases with income) of the tax have changed, comparing its structure at the end of the 1970s with its current version. Contrary to what might be expected from the reduction in top marginal tax rates, after 40 years the Italian personal income tax is more redistributive and slightly more globally progressive. A simple decomposition enables one to appreciate the importance that policy choices, inflation and the evolution of income distribution have had in shaping its effects over time. The lack of automatic adjustment mechanisms to inflation has produced a strong monetary fiscal drag effect, dampening the progressivity of the tax and increasing its burden. Policy changes, however, managed to make the tax more redistributive, and not less progressive. Compared with 40 years ago, the incidence of the tax has decreased on lower incomes, while increasing on middle and high incomes.

中文翻译：

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意大利个人所得税的再分配和累进性，40 年后

意大利个人所得税的结构自 1974 年推出以来经历了几次重要的变化，其路径与其他发达经济体类似。这些修改以一种先验不易识别的方式影响了其重新分配的影响，因为它们经常朝着不同的方向移动。本文的目的是研究税收的再分配效应（即税收减少税后收入不平等的能力）和累进性（即税收发生率随收入增加的比率）如何变化，比较其1970 年代末的结构及其当前版本。与降低最高边际税率的预期相反，40 年后，意大利的个人所得税更具再分配性，且在全球范围内更具渐进性。一个简单的分解使人们能够理解政策选择、通货膨胀和收入分配的演变在塑造其长期影响方面的重要性。缺乏对通胀的自动调整机制，产生了强烈的货币财政拖累效应，抑制了税收的累进性，增加了税收负担。然而，政策变化设法使税收更具再分配性，而不是渐进性降低。与 40 年前相比，低收入人群的税收负担有所下降，而中高收入人群的税收负担则有所增加。抑制税收的累进性并增加其负担。然而，政策变化设法使税收更具再分配性，而不是渐进性降低。与 40 年前相比，低收入人群的税收负担有所下降，而中高收入人群的税收负担则有所增加。抑制税收的累进性并增加其负担。然而，政策变化设法使税收更具再分配性，而不是渐进性降低。与 40 年前相比，低收入人群的税收负担有所下降，而中高收入人群的税收负担则有所增加。