I'm curious how they took into consideration the fact that recent immigrants can often fall into the lower social classes while having many connections to famil

I'm curious how they took into consideration the fact that recent immigrants can often fall into the lower social classes while having many connections to family and friends in their home country. Edit: It seems like they didn't even look at the social class of the people they interviewed. They just focused on the GDP of their country which doesn't make any sense imo.