Exit, Voice and Political Change: Evidence from Swedish Mass Migration to the United States A Comment

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 find that their analysis fails to recognize that their independent variable of interest, emigration, is severely underreported since approximately 30% of all Swedish emigrants are missing from their data. As a result, their instrumental variable estimator is inconsistent due to nonclassical measurement error. Another important problem is that their instrument is unlikely to be conditionally exogenous due to insufficient control for confounders correlated with their weather-based instrument. Indeed, they fail to properly account for non-linearities in the effect of weather shocks and to control for unobserved heterogeneity at the weather station level. Correcting for the any of these problems reveals that there is no relationship between emigration and political outcomes.