Zeros, Quality and Space: Trade Theory and Trade Evidence
利用双边产品级数据中的出口零值和出口单位价值等模式，检验主流贸易理论，发现现有模型无法完全解释这些事实，进而提出一个能解释所有事实的Melitz模型变体，其中高质量企业最具竞争力。
Bilateral, product-level data exhibit a number of strong patterns that can be used to evaluate international trade theories, notably the spatial incidence of “export zeros” (correlated with distance and importer size), and of export unit values (positively related to distance). We show that leading theoretical trade models fail to explain at least some of these facts, and propose a variant of the Melitz model that can account for all the facts. In our model, high quality firms are the most competitive, with heterogeneous quality increasing with firms' heterogeneous cost.