Collaborative Research: International Buyer-Seller Matches

国际贸易是个体买家和卖家持续互动的结果。从历史上看，官方统计数据只显示了它们的活动产生的总贸易量。很自然地，贸易理论试图对这些聚集进行建模，而很少关注隐藏在视线之外的个体相互作用的作用。一个限制是，研究无法深入探讨贸易远距离下降或贸易对国际价格变化反应迟缓等现象的根本原因。本研究利用来自美国、哥伦比亚和中国的最新国际交易数据，研究个别出口商和进口商之间的贸易关系。该项目有四个组成部分。首先是构建面板数据集，通过国际交易将国内买家和外国卖家联系起来。每一批商业货物都会生成一份海关记录，显示进出口公司的身份。此外，美国、哥伦比亚和中国都收集了大量关于本国生产商的公司或工厂层面的面板数据。通过将中国-美国出货量和哥伦比亚-美国出货量与这些生产者层面的调查合并，该项目的研究人员将创建大型面板数据集，跟踪一段时间内的进口商和出口商关系，以及每笔交易双方的当前状态信息。这些数据集将允许对有关贸易动态和公司一级业绩的广泛问题进行非常详细的分析。它们将通过人口普查局提供给所有经过适当安全许可的研究人员，并将为本项目剩余部分的进一步分析提供基础。该项目的下一个组成部分将审查根据出货数据生成的贸易统计数据的质量。一个国家报告的出口与另一个国家报告的相应进口之间的不一致一直困扰着对国际贸易的分析。例如，哥伦比亚报告的2007年向美国出口的商品与美国报告的从哥伦比亚进口的商品相差8%。这些数据集提供了诊断差异的工具。综合起来，例如，出口国和进口国的装运记录显示，在总体统计中是否出现差异，因为它们是基于不同的装运或对相同装运的不同估值。这项研究的这一部分应有助于贸易统计数据的编制。该项目的第三个组成部分将描述买方和卖方的互动。这些数据集通过它们的贸易关系将公司相互联系起来。网络理论为描述网络成员之间潜在的非常复杂的连接提供了各种度量标准，是解释这些连接的自然手段。因此，这些指标提供了洞察力，例如，了解一个联系广泛的单一买家或卖家对国际贸易的贡献程度。匹配的数据集将允许观察不同类型的公司相互之间形成联系的倾向。Copula理论为描述不同类型企业的匹配行为提供了一种自然的方法。例如，初步证据表明，大公司和小公司在与其他大公司或小公司的匹配程度上几乎没有区别。就大小而言，换句话说，匹配既不是积极的，也不是消极的分类。例如，该研究的这一部分提供了洞察力，以了解贸易对单一实体可能崩溃的脆弱性，以及贸易增长在多大程度上是新的贸易关系或现有关系内贸易扩大的结果。该项目的最后一个组成部分将使用这些数据来指导国际贸易经济模型的设计。认识到个别交易的离散性质和所涉个别公司的行为，需要对国际贸易理论进行彻底的重新表述。网络形成的动力学可以用一组成对的生成-重组过程来描述。因此，一个相当缺乏关于行为的具体假设的通用模型可以用来检验一大类经济模型必须满足的特征，以解释数据的基本特征。然后，研究将转向将交易关系与其他决策(如招聘和投资)联系起来的公司行为的具体表述。这项研究的这一部分应有助于发展反映个别公司相互作用的以计量为基础的国际贸易动态理论。

International trade is the outcome of ongoing interaction between individual buyers and sellers. Official statistics have historically revealed only the aggregate trade flows that their activity generates. Quite naturally, trade theory sought to model these aggregates with little attention to the role of individual interactions, which were hidden from view. A limitation is that research was unable to delve into the underlying reasons for such phenomena as the decline of trade with distance or the sluggish response of trade to changes in international prices. This research exploits newly available data on individual international transactions, from the United States, Colombia, and China, to study the trading relationships among individual exporters and importers. The project has four components. The first is the construction of panel datasets linking domestic buyers and foreign sellers through their international transactions. Each commercial shipment generates a customs record that reveals the identity of both the importing and exporting firm. In addition, the United States, Colombia and China all collect extensive firm- or plant-level panel data on their domestic producers. By merging China-U.S. shipments and Colombia-U.S. shipments with these producer-level surveys, the researchers on this project will create large panel data sets that follow importer-exporter relationships through time, with information on the current state of both parties to each transaction. These data sets will permit very detailed analyses of a wide range of issues concerning trade dynamics and firm-level performance. They will be made available through the Census Bureau to all researchers with the proper security clearance, and they will provide the basis for further analysis within the remainder of this project. The next component of the project will examine the quality of trade statistics generated from the shipments data. Inconsistency between exports reported by one country and the corresponding imports reported by another has plagued the analysis of international trade. For example, what Colombia reports exporting to the United States in 2007 differs by 8 percent from what the United States reports importing from Colombia. These datasets provide a tool to diagnose the discrepancies. Combined, the shipment records of the exporting and importing country reveal, for example, whether discrepancies arise in the aggregate statistics because they are based on different sets of shipments or different valuations placed on the same shipments. This component of the research should prove useful to the construction of trade statistics. The third component of the project will describe buyer-seller interactions. These datasets connect firms to each other through their trading relationships. Network theory, which provides various metrics for describing the potentially very complex connections among members of a network, is a natural means of interpreting these connections. The metrics thus provide insight, for example, into the extent to which a single widely-connected buyer or seller contributes to international trade. The matched datasets will allow the observation of the propensity with which different types of firms form links with each other. Copula theory provides a natural means of describing the matching behavior of different types of firms. Preliminary evidence suggests, for example, little tendency for large firms and small firms to differ in the extent to which they match with other large or small firms. In terms of size, in other words, matching is neither positively nor negatively assortative. This component of the research provides insight, for example, into the vulnerability of trade to the potential collapse of a single entity and the extent to which growth in trade is the consequence of new trading relationships or expansion of trade within existing ones. The final component of the project will use the data to guide the design of economic models of international trade. Recognizing the discrete nature of individual transactions and the behavior of individual firms involved requires a radical reformulation of international trade theory. The dynamics of network formation can be described in terms of a paired set of generation-recombination processes. A generic model that is fairly devoid of specific assumptions about behavior can thus be applied to examine features that a wide class of economic models must satisfy to explain basic features of the data. The research will then turn to specific formulations of firm behavior that connect trading relationships to other decisions, such as hiring and investment. This component of the research should prove useful to the development of a measurement-based dynamic theory of international trade that reflects the interaction of individual firms.