Entrepôt: Hubs, Scale, and Trade Costs
研究了全球贸易网络，发现80%的贸易通过间接运输，主要经由转口港枢纽完成，并量化了其贸易和福利影响，对理解贸易网络和基础设施政策有参考价值。
We study the global trade network and quantify its trade and welfare impact. We document that the trade network is a hub-and-spoke system where 80 percent of trade is shipped indirectly and largely via entrepôts—major hubs that facilitate trade between many origins and destinations. We estimate indirect-shipping-consistent trade costs using a model where shipments can be sent indirectly through an endogenous transport network and develop a geography-based instrument to estimate scale economies in shipping. Network and scale effects propagate local trade cost changes globally. Counterfactual infrastructure improvements at entrepôts generate ten times the global welfare impact relative to nonentrepôts.