Measuring Immigrant Generations Across the Life Course: Evidence from the National Longitudinal Survey of Youth 1979

Immigrant-generation comparisons underpin sociological accounts of incorporation, stratification and the life course, yet their validity depends on how longitudinal surveys record migration and family origins. We assess the U.S. National Longitudinal Survey of Youth 1979 (NLSY79) as a resource for such research. Respondent and parental birthplace classified 12,041 of 12,686 participants (94.9%): 863 first-generation, 772 second-generation and 10,406 third-or-higher-generation respondents. Thirteen overlapping self-reported ancestry families were measurable for all first- and second-generation respondents; 12.3% and 23.3%, respectively, reported multiple families. First-entry timing was available for 71.4% of first-generation respondents and entry status for 70.2%. Classification loss varied by sex and historical racial/ethnic cohort, detailed public-use birthplace was unavailable and several intersectional cells were small. These findings show why immigrant generation, ancestry, arrival timing and racialised position should not be treated as interchangeable indicators. The NLSY79 supports broad generation comparisons and selected arrival-timing analyses, provided researchers disclose classification rules, denominators and subgroup constraints. The study offers an auditable measurement foundation for longitudinal sociology of migration and inequality.