Latent Exports: Almost Ideal Gravity and Zeros
基于近乎理想的引力模型，测算了出口企业在目的地市场达到盈亏平衡点的距离，并利用Tobit模型对75个国家25个行业2006年的贸易流进行估计，发现可变贸易成本（距离和关税）比固定贸易成本（进入成本）和收入变化更能解释零贸易流。
Abstract Export promotion at the extensive margin is a key concern of governments. We develop measures of how far firms in origin sectors are from break-even entry in destination markets. The measure is based on Almost Ideal gravity featuring heterogeneous price and income elasticities. Tobit estimation of 2006 trade flows for 75 countries and 25 sectors generates latent trade bias (LTB)—the latent (projected) trade share of nonpartners minus the as-if-frictionless trade share. Explained LTB variance decomposition shows that variable trade costs (distance and tariffs together) account for zero flows more than do fixed trade costs (entry cost) and income variation.