New Immigrant Inflows and the Economic and Cultural Assimilation of Existing Immigrants, 1900-1930
How do existing immigrants respond to new immigration? New immigrant waves create competing pressures: they can accelerate assimilation, as earlier arrivals seek to differentiate themselves from newcomers, or hinder assimilation by increasing its costs. This paper studies the effect of new immigrant inflows on the economic and cultural assimilation of existing immigrants in the U.S. from 1900--1930. Using a shift-share instrument and linked census records, I estimate the effects of new inflows on existing immigrants' occupational outcomes and fertility. Aggregate inflows improve occupational standing, but co-ethnic inflows attenuate these gains through within-group labor market competition. Despite these gains, existing immigrants fail to close the gap with natives, who also benefit from immigration, slowing economic assimilation. Culturally, aggregate inflows push immigrants toward native fertility levels, consistent with assimilation as social differentiation, while co-ethnic inflows attenuate this effect, consistent with raising the costs of assimilation. Together, these results highlight how continued immigration shapes both the labor market trajectories and cultural integration of existing immigrants.