Is Denmark a Much More Educationally Mobile Society than the United States? Comment on Andrade and Thomsen, "Intergenerational Educational Mobility in Denmark and the United States" (2018)

I evaluate Andrade and Thomsen (A&T)’s (2018) study, which concludes that Denmark is significantly more educationally mobile than the United States. I make three observations. First, A&T overstate the difference in educational mobility between Denmark and the United States. Both in international comparison and compared with differences in intergenerational income mobility, A&T’s reported country differences in educational mobility are negligible. For example, whereas income mobility estimates reported in the literature differ by 300 to 600 percent between the two countries, the corresponding educational mobility estimates that A&T report differ by 10 to 20 percent. Second, I provide evidence suggesting that A&T’s use of crude categorical education measures leads them to overstate these negligible differences. Third, A&T’s empirical analyses of the U.S. data contain several statistical and data-related flaws, some so severe that they potentially undermine the credibility of their analyses. In sum, A&T’s results are perfectly consistent with the existence of a mobility paradox very similar to what Sweden–United States comparisons show: although Denmark and the United States are dissimilar with respect to income mobility, they are similar with respect to educational mobility. Understanding the nature of this paradox should be a key concern for future mobility research.