The COVID-19 pandemic significantly altered US domestic migration trends. Many individuals relocated from larger to smaller cities, a shift deviating from established patterns. This study explores the often-overlooked role of extended family in this change. Motivated by prior research indicating an inverse relationship between family ties and population size, the researchers hypothesize that individuals migrated closer to kin during the pandemic. The pandemic, by partially decoupling geographical location and economic opportunity, created a unique context to test this hypothesis. The study focuses on parental relationships due to their prominent role in intergenerational support and the age demographics of individuals most likely to migrate. The overall aim is to empirically investigate the relationship between pandemic-induced migration, city population size, and the influence of non-coresident family, particularly parental ties, on migration decisions.

The study draws upon three main lines of research. First, the 'family ties perspective' emphasizes the importance of family support, the need for proximity, and the unique nature of kinship in migration decisions. Family ties provide crucial social and practical support, and face-to-face interaction is often irreplaceable by virtual communication. Second, research on crises reveals that social ties, particularly kinship ties, are often activated during times of upheaval. Studies of previous crises show increased reliance on kin for support. Third, the study acknowledges the tension between economic aspirations and family orientation, suggesting that individuals may prioritize one over the other depending on circumstances. The COVID-19 pandemic, with its shift to remote work and economic uncertainty, provided a unique context where family ties might outweigh economic considerations in migration decisions. The study focuses on parental relationships due to their prominence in intergenerational support and the age demographics of individuals most likely to migrate.

The study employs a mixed-methods approach combining large-scale datasets: county-to-county relocation indices from anonymized mobile phone GPS data (Spectus), and individual-level information from the US Census American Community Survey Public Use Microdata Samples (ACS PUMS). Spectus data offers high temporal resolution, capturing real-time migration, while ACS PUMS provides individual-level demographic and migration information. The study conducts three investigations. Investigation 1 uses ACS PUMS to analyze individual-level migration patterns to assess whether individuals moved closer to parental family after the pandemic’s onset. Three types of moves are identified: individuals moving to their parents' homes, individuals returning to their native state (not with parents), and family households relocating to their native state. The migration rate (λm(t)) for each move type (m ∈ {1, 2, 3}) is calculated for each year (t) from 2016 to 2021. Investigation 2 develops a proxy variable (vi) estimating the abundance of households with potential parents to adult children in each US city, based on age and marital status criteria from the 2019 IPUMS USA sample. A PUMA-to-CBSA geo-allocation mapping algorithm is used to obtain city-level estimates. This proxy variable is related to city population size and net migration. Net migration (yi(t)) is calculated using Spectus data, representing the inflow per outflow of city i during week t. Investigation 3 uses a difference-in-differences (DiD) model with a continuous treatment variable (vi) to analyze the relationship between parental family availability and changes in net in-migration during and after the pandemic. The model controls for various factors including population size and density, median home value, median income, employment level, and the share of single-family homes. Log-ratios of net in-migration are analyzed (yi(θ=1)/yi(θ=0)).

The study's key findings are as follows: 1. **Increased Migration from Large to Small Cities:** Analysis of Spectus data reveals a significant increase in migration from large to small cities after the pandemic's onset. Cities smaller than 500,000 saw a substantial influx of people from cities larger than 500,000. This influx accounted for a significant portion of the increase in net in-migration for smaller cities. 2. **Micro-level Dynamics of "Moving Back Home":** Analysis of ACS PUMS data shows an increase in various types of "return-to-home" migration in 2020 and 2021, especially for individuals moving to their parents' households (Type 1 moves). This suggests increased reliance on parental support during the pandemic. 3. **Correlation Between Parental Family Availability and Net Migration:** The developed proxy variable (vi) for parental family availability shows a negative correlation with city population size and a positive correlation with increases in net in-migration after the pandemic's onset. Cities with greater parental family availability experienced larger positive changes in net in-migration. 4. **Empirical Model Results:** The difference-in-differences model confirms the positive and statistically significant relationship between parental family availability and changes in net in-migration, even after controlling for factors such as population density and cost of living. This result supports the central hypothesis, indicating that extended family proximity played a significant role in shaping migration patterns during the pandemic.

The findings support the central proposition that extended family ties played a substantial role in the shift towards smaller cities during the COVID-19 pandemic. The results demonstrate that while economic and physical factors influenced migration, the role of family cannot be neglected. The study enhances the family ties perspective and migration literature, suggesting the importance of considering family ties, particularly parental relationships, in migration models. The pandemic seemingly caused a re-prioritization of family proximity over economic aspirations for many individuals, as indicated by increased migration towards smaller cities and places of birth. This suggests a potential tension between the economic success of large cities and the social well-being of their residents.

This study provides robust empirical evidence, using multiple data sources, that the increased migration to smaller cities during the COVID-19 pandemic was partly driven by the increased migration towards non-coresident family. The heterogeneous spatial distribution of family ties in the U.S., where people are more likely to have family in smaller cities, is a crucial factor. This research emphasizes the significant role of broader kinship systems, extending beyond nuclear families, in large-scale socioeconomic phenomena. Future research could explore the long-term consequences of this pandemic-induced migration and investigate the role of other extended family members beyond parental ties.

The study's main limitation stems from the reliance on proxy variables for family location due to data limitations. Direct measurement of individual family networks with detailed geographic information was not possible. Combining analyses at different levels helps to mitigate this limitation, but future research with more comprehensive data would strengthen the conclusions. Additionally, the focus primarily on parental ties limits the understanding of the broader impact of extended kin. The availability of improved data on extended family location is crucial for refining and extending these findings.