What about immigration? The closed-population assumption in research on intergenerational income mobility

Research on intergenerational income mobility is highly informative and increasingly popular. A neglected aspect of these studies, however, is their implicit target population. Studies of income mobility are typically biased toward the representation of third-and-higher-generation persons. We refer to this practice as the closed-population assumption. First-generation, second-generation, and undocumented immigrants are less likely to be included because adequate data on income for their parental generation is more likely to be missing. Given significant international migration, ignoring the foreign stock is potentially inaccurate when making generalizations about entire societies. We discuss analytical issues associated with the closed-population assumption and provide some exploratory findings, which suggest significant interrelationships between emigration and intergenerational, income mobility.