Collaborative Research: A Unified Approach to Spatial Economics

在过去的几年里，贸易经济学家已经开始开发一般均衡模型，在这些模型中，国家大小和距离在决定均衡贸易关系方面发挥着关键作用。本研究旨在促进对一般均衡空间模型的理解，并特别强调其政策含义。研究人员首先构建了一个包含大量一般均衡经济模型的综合空间框架，在这些模型中，许多地点通过一个或多个空间联系(如贸易、通勤、空间知识溢出)联系在一起。这个项目进一步开发了新的工具来描述这些模型的均衡和在这些设置中的最优政策的理论和经验性质。最后，调查人员利用框架和工具解决一些重要的政策问题，例如：基础设施投资项目的经济影响是什么；在城市和社区内应如何最好地设计基于位置的政策；冲击对整个空间的经济发展演变有什么影响？这项研究的范围包括六个项目：(1)具有单一空间联系的贸易和地理模型的积极性质和相对静态影响的分析；(2)具有任意数量的空间联系的空间模型均衡的积极性质的分析；(3)在存在空间知识溢出的情况下使用城市模型描述芝加哥境内土地的最佳利用的特征；(4)美国国内最优交通基础设施改善的特征；(5)路径依赖在美国经济随时间的演变中的重要性的量化；以及(6)移民政策的福利影响分析。这些项目有可能以多种方式促进知识的发展，包括：(1)它通过提供适用于研究多种类型的空间相互作用的单一统一框架，帮助整合贸易、经济地理和城市经济学领域；(2)它概括地描述了空间均衡的积极性质；(3)它开发了新的工具，对现实世界经济现象的空间模型进行实证分析，并描述最优空间政策。

In the past few years, trade economists have begun developing general equilibrium models where country size and distance play a crucial role in the determination of the equilibrium trade relationship. This research aims at advancing the understanding of general equilibrium spatial models, with special emphasis on their policy implications. The investigators first construct an integrated spatial framework encompassing a large number of general equilibrium economic models in which many locations are connected through one or more spatial linkages (e.g. trade, commuting, spatial knowledge spillovers). This project further develops new tools to characterize both the theoretical and empirical properties of the equilibrium of such models and optimal policy in these setups. Lastly, the investigators apply the framework and tools to address a number of important policy questions such as: what are the economic impacts of infrastructure investment projects; how should one best design location-based policies within cities and communities; and what are the effects of shocks on the evolution of economic development across space? The scope of this research comprises six projects: (1) an analysis of the positive properties and comparative static implications for trade and geography models with a single spatial linkage; (2) an analysis of the positive properties of the equilibrium of spatial models with an arbitrary number of spatial linkages; (3) a characterization of the optimal use of land within Chicago using an urban model in the presence of spatial knowledge spillovers; (4) a characterization of the optimal transportation infrastructure improvements within the United States; (5) a quantification of the importance of path dependence in the evolution of the U.S. economy over time; and (6) an analysis of the welfare implications of immigration policy. These projects have the potential to contribute to the advancement of knowledge in a number of ways, including: (1) it helps to integrate the fields of trade, economic geography, and urban economics by providing a single unified framework suitable for the study of many types of spatial interactions; (2) it offers a general characterization of the positive properties of spatial equilibria; and (3) it develops new tools to conduct the empirical analysis of spatial models on real world economic phenomena and characterize optimal spatial policies.