What Are the Consequences and Determinants of Trade Protection?

本研究探讨了国际经济学研究的核心问题：第一，贸易政策（进口关税等）对进出口、关税收入等经济结果有何影响？ 第二，在任何特定时间，哪些社会群体相对受到贸易政策的青睐？经济学家使用复杂的数值模拟来回答第一个问题，既为了评估已经发生的政策变化，也为了预测政策建议的潜在后果。该项目的研究开发了新的统计程序，可用于评估此类模拟的有效性。如果这种模拟通过了这些有效性检验，就可以用来量化进出口如何影响不同社会群体的真实的收入（例如，根据他们的就业部门或居住地区）。然后，在项目中使用这些估计影响的模式，以了解任何给定政策（例如当前针对给定的利益设置的）受益和/或损害不同的群体，而不需要对这一政策是如何达成的或其起源背后的既定目标采取立场。本研究的第一个组成部分侧重于贸易的福利后果保护从历史上看，对这种影响的估计一直依赖于定量贸易模型的反事实模拟。为了帮助评估和潜在地加强定量贸易模型预测的可信度，本研究开发了一种新的测试程序，该程序直观，易于实施，并与该领域的标准实践相一致。然后，这一程序适用于2018年美国和某些贸易伙伴之间发生的巨大关税变化。第二部分着重于贸易保护的政治经济决定因素。出发点是一个新的和一般的最优关税公式，依赖于假设贸易税是帕累托有效的约束，但在其他方面不需要对优惠，技术，市场结构或政治进程的具体情况进行任何限制。这一公式突出了最优关税如何随着社会不同组成部分的帕累托权重而变化-这反映了贸易保护的政治决定因素-以及进口的边际变化如何影响其真实的收入-这反映了贸易保护的经济决定因素。从经验上讲，研究首先估计这些经济决定因素（与第一个组成部分相同的2018年背景下），然后将它们与最优关税的新公式相结合，以估计在观察到的贸易政策横截面变化的情况下必须使用的帕累托权重。在对保护的政治决定因素进行非参数估计的基础上，研究的最后一步旨在量化贸易政策的主要政治经济模型可以解释的程度。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This research examines two questions that are at the heart of the study of international economics: First, what effects do trade policies (such as import tariffs) have on economic outcomes such as imports, exports, and tariff revenue? And second, which groups of society are relatively favored by the trade policy that is in place at any given time? Economists use elaborate numerical simulations to answer the first of these questions, both in order to evaluate policy changes that have already happened and to predict the potential consequences of policy proposals. The research in this project develops new statistical procedures that can be used to assess the validity of such simulations. Provided such simulations pass these validity tests, they can then be used to quantify how imports and exports impact the real incomes of different groups of society (based, for example, on their sector of employment or their region of residence). The patterns of such estimated impacts are then used in the project to understand the extent to which any given policy (such as the one currently in place for a given setting of interest) benefits and/or harms distinct groups, without the need to take a stand on how that policy was arrived at or what stated goals may have been behind its origination.The first component of this research focuses on the welfare consequences of trade protection. Historically estimates of such impacts have relied on the counterfactual simulations of quantitative trade models. To help assess and potentially strengthen the credibility of the predictions of quantitative trade models, this research develops a new testing procedure that is intuitive, easy to implement, and consistent with standard practices in the field. This procedure is then applied to the dramatic tariff changes that took place among the United States and certain trading partners in 2018. The second component focuses on the political-economy determinants of trade protection. The starting point is a new and general optimal tariff formula that relies on the assumption that trade taxes are constrained Pareto efficient, but otherwise does not require any restriction on preferences, technology, market structure or the specifics of the political process. This formula highlights how optimal tariffs vary with the Pareto weights of different constituents of society -- which reflects the political determinants of trade protection -- as well as how marginal changes in imports affect their real earnings -- which reflects the economic determinants of trade protection. Empirically, the research begins by estimating these economic determinants (in the same 2018 context as for the first component) and then combines them with the new formula for optimal tariffs in order to estimate what Pareto weights must be given the observed cross-sectional variation in trade policy. Armed with such non-parametric estimates of political determinants of protection, a final step of the research seeks to quantify the extent to which they can be accounted for by leading political-economy models of trade policy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.