That’s because (legal) immigrants have high social capital (education, values, two parent households) and often migrate to places where they have the highest re

That’s because (legal) immigrants have high social capital (education, values, two parent households) and often migrate to places where they have the highest relationship capital (hence the CountryVille neighborhoods like Koreatown or the Ukrainian neighborhood on the East side of Manhattan). So when you measure their kids income it jumps up on average.