Historical Patterns in the Intergenerational Transmission of Lifespan and Longevity: A Research Note on U.S. Cohorts Born Between 1700 and 1900

This research note examines historical trends in lifespan inequality and the intergenerational transmission of lifespan and longevity in the United States over the eighteenth, nineteenth, and twentieth centuries. We contribute to the literature by expanding estimates of the familial component beyond parent–child associations to include multigenerational and horizontal classes of relatives of different sexes. We also examine how lifespan inequality and the role of the family in lifespan and longevity changed over time. To address the challenge of studying extended family networks in historical times, we leverage recent online crowdsourced genealogical data. Results confirm the presence of a familial component for all classes of relatives considered and highlight a stronger association for horizontal than for vertical relationships. Despite decreasing lifespan inequality, we find no evidence of decreased familial lifespan stratification throughout history. If anything, the results suggest a strengthening of the parent–child association. Finally, our findings contribute to the debate on the representativeness and usability of crowdsourced genealogical data by emphasizing the importance of sample selection based on the quality of the information collected.