The State Capacity Ceiling on Tax Rates: Evidence From Randomized Tax Abatements in the DRC
中文摘要
本文研究税率与税收执法如何共同影响低收入国家的财政能力。我们研究了刚果民主共和国的一项政策实验，该实验将38,028名财产所有者随机分配至维持现行税率组或降低税率组。税负的这一变动表明，现行税率高于收入最大化税率（RMTR）。将税率降低约三分之一，将通过提高税收遵从度使政府收入最大化。随后，我们利用执法方面的两个变异来源——随机化的执法信函与税收征收员的随机分配——表明RMTR随执法力度增强而提高。在税务信函中加入执法信息，或将执法能力处于最低四分位的征收员替换为执法能力处于平均水平的征收员，均可使RMTR提高约40%。因此，税率与执法是互补的政策杠杆。对税率与执法进行联合优化所带来的收入增益，将比对二者分别优化高出10%。这些发现提供了实验证据，表明在部分发展中国家，政府执法能力较低对收入最大化税率构成了具有约束力的上限，从而说明了在提高税率的同时加强执法，对于扩大财政能力的价值。
Abstract
This paper investigates how tax rates and tax enforcement jointly impact fiscal capacity in low‐income countries. We study a policy experiment in the D.R. Congo that randomly assigned 38,028 property owners to the status quo tax rate or to a rate reduction. This variation in tax liabilities reveals that the status quo rate lies above the revenue‐maximizing tax rate (RMTR). Reducing rates by about one‐third would maximize government revenue by increasing tax compliance. We then exploit two sources of variation in enforcement—randomized enforcement letters and random assignment of tax collectors—to show that the RMTR increases with enforcement. Including an enforcement message on tax letters or replacing tax collectors in the bottom quartile of enforcement capacity with average collectors would raise the RMTR by about 40%. Tax rates and enforcement are thus complementary levers. Jointly optimizing tax rates and enforcement would lead to 10% higher revenue gains than optimizing them independently. These findings provide experimental evidence that low government enforcement capacity sets a binding ceiling on the revenue‐maximizing tax rate in some developing countries, thereby demonstrating the value of increasing tax rates in tandem with enforcement to expand fiscal capacity.