Amy Chua and Jed Rubenfeld wrote a book titled "The Triple Package: How Three Unlikely Traits Explain the Rise and Fall of Cultural Groups in America".
This book examines why certain groups of people are more successful than the general US population. The authors argue that the interplay of a superiority complex, feelings of insecurity, and impulse control is what drives certain groups to work hard and succeed. These people aren't anymore intelligent than the rest of us; they're just driven because they have a chip on their shoulder and their upbringing provides them the "grit" to not give up when the situation is difficult. For these people, the American Dream is alive and well. They are very upwardly mobile. These are some of the groups that the authors looked at:
Mormons: Mormons make up only 1.7% of the US population but many have achieved financial and political success. Some successful mormons include Mitt Romney, Senators Reid and Hatch, David Neeleman (founder of Jet-Blue),Glenn Beck, Stephenie Meyer, Gary Baughman (CEO of Fisher-Price), and Ken Jennings (Jeopardy champ). Since 1990, there have been 14 senior executives in Fortune 500 companies. The LDS church owns lots of land (larger than the state of Delaware); it also has an estimated $25 to $30 billion in assets as of 1997.
Cuban exiles: These people left Cuba by the thousands with no more than five dollars in their pockets after 1961 and settled in Miami. As of 2004, over 30% of Cuban Americans held managerial and professional positions. Today, the total revenue of Cuban American businesses exceed that of Cuba. By 1990, nearly 37% of these exiles' children earned more than $50,000/year compared to 18% by Anglo-Americans.
Nigerians: In 2010, Nigerians (0.7% of the total US black population) accounted for 20 to 25% of the black students at Harvard Business School; they're overrepresented among black students at elite US colleges by a factor of 10. Nigerians also make up about 10% of the nation's black physicians. Almost 25% of Nigerian households make over $100,000/year with a median household income of $58,000/year compared to the national median of $51,000/year.
Asians: Asians and asian-americans make up 30 to 50% of the student bodies at the top music programs such as the Juilliard School of Music. Indians have won the national spelling bee 5 years straight. In 2012, 48 out of 141 US Presidential Scholars were asians. Asian SAT scores are 143 pts above average. Asians are about 5% of the US population but make up 19% of the undergrad student body at Harvard, 16% at Yale, 19% at Princeton and Stanford.
Indian Americans have the highest median income of any Census-tracked ethnic group in the US ($90,500/year); the national median income is $51,200.
Da Jews: Jews make up 1.7% of the US population. They have the highest median income of any ethnic/religous group ($98,000). In the Forbes 400 richest Americans, there are 139 jews.