The log of gravity
The log of gravity
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DOI：
10.1162/rest.88.4.641
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发表时间：
2006-11-01
影响因子：
8
通讯作者：
Tenreyro, Silvana
中科院分区：
文献类型：
--
作者：
Silva, J. M. C. Santos;Tenreyro, Silvana
虽然经济学家们早就意识到了詹森不等式，但许多计量经济学应用都忽略了它的一个重要含义：在异方差下，OLS估计的对数线性化模型的参数导致对真实弹性的有偏估计。我们解释了为什么会出现这个问题，并提出了一个适当的估计。我们的批评传统的做法和建议的解决方案扩展到广泛的应用程序中的对数线性化方程估计。我们用一个特别的例子来展开论证，即贸易的引力方程。我们发现与建议的估计和传统的方法获得的估计之间的显着差异。
Although economists have long been aware of Jensen's inequality, many econometric applications have neglected an important implication of it: under heteroskedasticity, the parameters of log-linearized models estimated by OLS lead to biased estimates of the true elasticities. We explain why this problem arises and propose an appropriate estimator. Our criticism of conventional practices and the proposed solution extend to a broad range of applications where log-linearized equations are estimated. We develop the argument using one particular illustration, the gravity equation for trade. We find significant differences between estimates obtained with the proposed estimator and those obtained with the traditional method.