讲座：Supply Chain Management, Production Networks, and Aggregate Fluctuations
题 目：Supply Chain Management, Production Networks, and Aggregate Fluctuations
嘉 宾：Le Xu, Ph.D. candidate, University of Pennsylvania
主持人：许志伟 副教授 上海交通大学安泰经济与管理学院
时 间：2019年 12 月 19 日（周四） 14:30-16:00
地 点：上海交通大学 徐汇校区包图 A303
Over the business cycle, firms adjust not only their sales and input expenditures but also the number of suppliers from which they source from. I incorporate this extensive margin into a real business cycle model featuring input-output networks. Using a dataset of supply chain relationships among US firms, I first document that increases in the number of suppliers are correlated with increases in sales, intermediate input expenditures, total factor productivities, and costs of managing suppliers. Based on these facts, I develop a model in which firms trade off the productivity benefit (return to variety) of accessing more varieties with the (fixed) cost of managing these varieties. The extensive margin adjustment introduces a return to scale into production, which interacts with input-output networks and amplifies industry productivity shocks: In my estimated model, the effect of industry productivity shocks on GDP fluctuations is one-fourth larger than in a (conventional) model where the extensive margin is absent.
Le Xu is a Ph.D. candidate in Economics from the University of Pennsylvania. He also serves as a research analyst at the Federal Reserve Bank of Philadelphia. His research interests span macroeconomics, business cycles, and network economics.