论文标题
部分可观测时空混沌系统的无模型预测
Exit, Voice and Political Change: Evidence from Swedish Mass Migration to the United States; A Comment
论文作者
论文摘要
在此评论中，我重新审视了Karadja和Prawitz（2019）在大规模移民与长期政治成果之间存在因果关系的问题。我通过其工具变量分析讨论了许多潜在的问题。首先，至少有三个原因违反了排除限制：（i）无法控制内部迁移，（ii）与其工具相关的混杂因素的控制不足，以及（iii）用非经典测量误差测量的移民。其次，我还讨论了统计推断的两个问题，这两者都表明该仪器无法满足相关条件，即该仪器与内源性变量移民没有足够的相关性。纠正这些问题中的任何一个都表明，移民与政治结果之间没有关系。
In this comment, I revisit the question raised in Karadja and Prawitz (2019) concerning a causal relationship between mass emigration and long-run political outcomes. I discuss a number of potential problems with their instrumental variable analysis. First, there are at least three reasons why their instrument violates the exclusion restriction: (i) failing to control for internal migration, (ii) insufficient control for confounders correlated with their instrument, and (iii) emigration measured with a nonclassical measurement error. Second, I also discuss two problems with the statistical inference, both of which indicate that the instrument does not fulfill the relevance condition, i.e., the instrument is not sufficiently correlated with the endogenous variable emigration. Correcting for any of these problems reveals that there is no relationship between emigration and political outcomes.
