I thought I'd bring up the topic of ethnic integration in the US, in relation to locus of control, since I haven't seen this mentioned before.
American culture values: independence, personal success and entrepreneurship. Essentially, a society that highly favours an internal locus of control, a belief system that relates one's success or failure to internal factors, such as ability and hard work, as opposed to external factors, such as luck or difficulty of task.
An internal locus of control is often correlated to: educational achievement, promotions and in turn, higher income.
During the late 18th, 19th and early 20th centuries, various laws were passed in the US, which discriminated against chinese in the US, such as the: naturalization act of 1790, which limited citizenship to whites only, the 1882 chinese exclusion act and the immigration act of 1924, which banned chinese immigration.
However, discrimination and laws are not constants, as they are determined by current events. Fast forward to the current era.
Conversely, there appears to be more discrimination towards ethnicities, with an external locus of control:
Poll: Muslim-Americans face the most discrimination among ethnic/religious groups Â« Hot Air
There are numerous factors which can determine the successful integration of any ethnic minority group into a majority culture. However, I believe locus of control is an important factor in income attainment and discrimination reduction, as it pertains to the United States.