Refugee gravitation
Refugee gravitation
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DOI：
10.1007/s11127-016-0367-y
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发表时间：
2016-12-01
期刊：
影响因子：
1.6
通讯作者：
Gardeazabal, Javier
中科院分区：
文献类型：
--
作者：
Echevarria, Jon;Gardeazabal, Javier
本文利用引力模型研究了全球被迫移民的决定因素。我们发现，忽略零计数的结果在参数估计，低估了协变量对难民计数的影响。我们比较了合并回归，它不考虑未观察到的异质性，和固定效应的方法，它不确定时不变的协变量的影响，不能揭示太多的光时，协变量变化不大。我们提出了前样本均值广义矩量法（PSM-GMM）估计，它容纳零点，占未观察到的异质性，但没有固定效应的方法，当协变量表现出很小的变化的缺点。此外，使用最近开发的方法来估计标准误差，是强大的二元相关性，我们发现的证据表明，以前的研究结果的基础上低估的标准误差大多仍然有效，适当调整标准误差后，特别是，冲突和公民自由的来源国和邻近被发现是被迫迁移的重要决定因素。然而，一些先前被发现具有显著性的协变量，例如共享共同语言或具有殖民关系，失去了显著性。此外，我们发现，目的地国的公民自由程度对它接收的难民人数有着显著的积极影响，这是一种以前没有探讨过的机制。
This paper makes use of a gravity model to investigate the determinants of global forced migration. We find that omitting zero counts results in parameter estimates that underestimate covariate effects on refugee counts. We compare the pooled regression, which does not account for unobserved heterogeneity, and the fixed-effects method, which does not identify the effect of time-invariant covariates, and cannot shed much light when covariates vary little. We propose the pre-sample mean generalized method of moments (PSM-GMM) estimator, which accommodates the zeros, accounts for unobserved heterogeneity, but does not have the drawbacks of the fixed-effects methods when covariates exhibit little variation. In addition, using recently developed methods to estimate standard errors that are robust to dyadic correlation, we find evidence suggesting that previous findings based on underestimated standard errors mostly remain valid after properly adjusting standard errors; in particular, conflict and civil liberties in the source country and proximity are found to be significant determinants of forced migration. However, some covariates previously found to be significant, such as sharing a common language or having a colonial relationship, lose significance. In addition, we find a significant positive influence of the level of civil liberties in the destination country on the number of refugees it receives, a mechanism not explored before.