US migration from 1850 to 1920: A comparison of family trees with linked census data

The quality and representativeness of longitudinal datasets play a central role in historical migration research. In this study, we apply the child-ladder (CL) method to a population-scale family tree dataset to analyze U.S. interstate family migration from 1850 to 1920. The CL method infers moves from changes in birthplaces between successive children, allowing for more precise dating of migration events. However, it is limited to families with at least two children. To evaluate the representativeness and utility of family trees for migration research, we compare the CL data to the IPUMS Multigenerational Longitudinal Panel (MLP), which tracks household moves across census decades and serves as a proxy for broader population migration. The CL data reveal higher migration rates, suggesting a likely closer approximation to migration levels in the overall population. Also, by capturing intercensal and return migrations, the CL method provide a detailed view of migration patterns across space and time. Despite differences in migration rates, both datasets reveal similar regional migration structures, especially in the earlier periods. These findings show that population-scale family trees when analyzed using the CL method, offer a valuable complement to linked census data by enhancing our understanding of long-term U.S. migration patterns and regional divisions.