Who Benefits from Citizenship? Heterogeneous Effects of Naturalization Decisions in the Early Twentieth-Century United States

While existing research highlights the occupational advantages of citizenship for immigrants, little is known about how such advantages might vary, and previous studies have not fully dealt with issues of selection. We study the heterogeneous effects of naturalization by leveraging a novel historical dataset of naturalization records from New York City’s Southern District in the early 1900s. We link these to U.S. census data from 1920, 1930, and 1940, tracking 1,947 immigrants who declared their intent to naturalize, analyzing occupational trajectories among them, and modeling selection into naturalization using random forests. Our findings reveal that immigrants who completed the naturalization process attained significantly higher occupational status than those who initiated but did not complete naturalization. In addition, propensity-stratified results support a negative selection hypothesis: Immigrants less likely to naturalize enjoyed greater returns to naturalization, surpassing the unnaturalized in the high-propensity, more advantaged group. We support these results with supplementary analyses of full-count census data, where we find similar trends. These results underscore the role of naturalization as a key driver of socioeconomic mobility while highlighting citizenship as a critical stratifying force.