Thomas Sowell's Immigrations And Cultures goes into this in excruciating detail as he lays out that certain immigrant groups, because they are from particular areas, are going to do better than other similar immigrant groups, or even the originating population. The cultural practices that inform their success are down to even the street level, separated by time.

This is why you get shit like Pakistanis being horrified that Pakistani Grooming Gangs are just going on a hate-rape campaign in Britain: it's because we are explicitly importing pedophiles.