Abstract
Case studies of immigrant groups have contributed significantly to theoretical developments in the fields of immigration and ethnic studies. The focus on the immigrant group as a whole has resulted in ignoring immigrant subgroups, reducing ethnicity to national-origin. Ethnically diverse immigrant groups contain more than one type of ethnicity. Internal ethnicity refers to the presence of ethnic groups within an immigrant group. It is argued that, in the destination country, the immigrant subgroups who were already minorities in the country of origin are less assimilated than the immigrant subgroup which was part of the majority population. Survey data collected in a probability sample of Iranians in Los Angeles allow us to address this issue. Ethnicity of the Muslim majority in the United States is compared with that of Armenian, Bahai, and Jewish ethno-religious minorities from Iran. The data analysis supports the argument, and further shows that pre-migration ethnicity is an important and neglected aspect of post-migration ethnicity.