On the Problem of Endogenous Unobserved Effects in the Estimation of Gravity Models
On the Problem of Endogenous Unobserved Effects in the Estimation of Gravity Models
复制标题
论重力模型估计中的内生不可观测效应问题
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
P. Egger
中科院分区：
文献类型：
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作者：
P. Egger
我们建议用Hausman和Taylor(1981)的2SLS误差分量方法估计重力模型。首先，这可以解释一些回归变量与未观察到的影响之间的可能相关性，这一点在以前的研究中被忽略了。其次，与内部估计量不同的是，我们也可以在具有双边效应的框架内获得对时间不变变量的估计。我们表明，距离和国家大小是相关性的重要来源。正确估计的距离参数大约是有偏差的GLS参数的两倍，明显高于其他人的发现。
We propose to estimate gravity models by a Hausman and Taylor (1981) 2SLS error components approach. First, this allows to account for the possible correlation of some of the regressors with the unobserved effects, which has been ignored in previous research. Second and in contrast to the Within estimator, one obtains estimates for the time-invariant variables also in a framework with bilateral effects. We show that distance and country size are important sources of correlation. The properly estimated parameter of distance is about twice as high as its biased GLS counterpart and markedly higher than found by others.