Age at Arrival and Assimilation during the Age of Mass Migration

We estimate the effect of age at arrival for immigrant outcomes with a new dataset of arrivals linked to the 1940 U.S. Census. Using within-family variation, we find that arriving at an older age, or having more childhood exposure to the European environment, led to a more negative wage gap relative to the native born. Infant arrivals had a positive wage gap relative to natives, in contrast to a negative gap for teenage arrivals. Therefore, a key determinant of immigrant outcomes during the Age of Mass Migration was the country of residence during critical periods of childhood development.