گوه های تجارت، موجودی انبار و چرخه های کسب و کار بین المللی

Residuals of the import demand equation, the so-called “trade wedges”, are disturbingly large and persistent. This fact suggests substantial room for improvement in the standard formulation of import demand, particularly when applied to high-frequency changes over time. Alessandria, Kaboski, and Midrigan hypothesize that the real problem is failing to distinguish between the volume of imports and consumption of imported goods, the difference being the change in inventories of imported goods. In this view, the standard import demand equation applies to consumption of imports. It needs to be augmented with a model of inventory management to explain the volume of imports. Using a clever and tractable formalization, the paper integrates inventories neatly into a standard open-economy macro model, showing that it improves the standard model's predictions along several dimensions. It generates large fluctuations in trade volumes (due to the dynamics of inventories rather than trade wedges), countercyclical real net exports, and less correlation in consumption across countries. I want to make two points in this discussion. First, I show that trade wedges, if viewed from the perspective of bilateral trade flows, are also disturbing. Thus, I concur with the authors' motivation: it is a first-order problem to address. Second, I call attention to the neat model of inventories employed in this paper. I predict that this model will have many applications and extensions in future work. While I am not convinced that inventories are the main source of our problems in explaining import behavior over time, this paper certainly takes a step in the right direction.