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发展一般均衡模型，其中国家规模和距离在确定均衡贸易关系中发挥着至关重要的作用。本研究旨在促进对一般均衡空间模型的理解，特别强调其政策含义。研究人员首先构建了一个综合的空间框架，包括大量的一般均衡经济模型，其中许多地点通过一个或多个空间联系（例如贸易，通勤，空间知识溢出）连接。该项目进一步开发了新的工具来表征这些模型的均衡的理论和经验性质以及这些设置中的最优政策。最后，研究人员应用框架和工具来解决一些重要的政策问题，如：基础设施投资项目的经济影响是什么;如何最好地设计城市和社区内基于位置的政策;以及冲击对跨空间经济发展演变的影响是什么？本研究的范围包括六个项目：（1）分析具有单一空间联系的贸易和地理模型的正属性和比较静态含义：（2）分析具有任意数量空间联系的空间模型的均衡的正属性;（3）在空间知识溢出存在的情况下，利用城市模型对芝加哥内土地的最优利用进行表征;（4）描述美国境内最佳运输基础设施改善的特征;（5）量化路径依赖在美国经济随时间演变中的重要性;（6）分析移民政策的福利影响。这些项目有可能以多种方式促进知识的进步，包括：（1）通过提供适合于研究多种类型空间相互作用的单一统一框架，有助于整合贸易、经济地理学和城市经济学领域;（2）它提供了空间均衡积极特性的一般特征;（3）开发新的工具，对真实的世界经济现象进行空间模型的实证分析，并表征最优空间政策。

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.