Rooted America: Immobility and Segregation of the Inter-county Migration Networks

Abstract

Despite the popular narrative that the United States is a "land of mobility," its internal migration rates have declined for decades, and reached a historical low. Economic and related factors were able to account for a portion of this trend, but the bulk has remained unexplained. Here, we propose a systemic, relational model of internal migration in the U.S., combining demographic, economic, political, and geographical factors with endogenous social mechanisms, with the objective of identifying factors limiting migration rates. We implement this model using valued temporal exponential-family random graph models, allowing us to calibrate it to the (valued) network of intercounty U.S. migration flows during the 2011-2015 period. Our analysis reveals a pattern of segmented immobility, where fewer people migrate between counties with dissimilar political contexts, levels of urbanization, and racial compositions. Probing our model using"knockout" experiments suggests that one would have observed approximately 3 million (17%) more intercounty migrants over the study period were the segmented immobility mechanisms inoperative. This analysis suggests that internal migration in the current era is driven not only by demographic and economic factors, but also cultural and political ones. It also reveals social and political cleavages that underlie geographical immobility in America.

Keeping in Motion or Staying Put: Internal Migration in the United States and China

“…International migration remains an important topic, even in discussions of internal migration, as it is a key component in each country's geographic mobility and economic prosperity. The arrival of international immigrants to a county increases its mobility and does not increase net out-migration [4]. Furthermore, economies tend to respond to immigration with an increase in demand for labor, thus creating more jobs [73].…”

“…Huang and Butts proposed the concept of segmented immobility, arguing that internal migration is more relational than geographic because most people want to live near those who are similar to them along lines that are important to them [4]. They analyzed the impact of political partisanship, urbanization, and race on intercounty migrations from 2011 to 2015, and found that these factors immobilized migration between dissimilar counties, a significant finding as the U.S. becomes more politically divided, with a large percentage of the U.S. population living in neighborhoods comprised almost entirely of residents who vote like them [54].…”

“…Internal migration is defined as geographic mobility patterns within a country or political unit. Whether, why, and where people relocate is partly determined by financial, occupational, social, cultural, and political reasons [1][2][3][4][5][6]. Similar considerations contribute to a diverse range of migration characteristics among countries, states, and municipalities.…”