INVENTORIES, INPUT COSTS, AND PRODUCTIVITY GAINS FROM TRADE LIBERALIZATIONS
研究发现，贸易自由化中企业因进口增加而持有更多库存，这带来了额外成本；若忽略库存成本，会高估关税削减对生产率的提升效果，实际收益可能降低20%至50%。
Abstract Sourcing internationally allows firms to access cheaper or better inputs but increases logistical costs, particularly through higher inventory holdings. This article examines the productivity gains from trade liberalizations accounting for inventory costs—typically omitted from revenue‐based measures of productivity. In model simulations, we show that omitting these overestimates the effect of input tariffs on productivity and that controlling for inventories in the estimation of productivity corrects the bias. We document these facts during India's 1990s reforms. First, firms' inventories increase strongly with imports. Second, productivity gains drop by 20–50% once inventory costs are accounted for.