By definition, in order to study social mobility one needs to focus on characteristics that can change. Traditionally, social scientists have focused on class mobility or geographic mobility rather than mobility along other axes of social inequality, such as race or gender, because the latter characteristics are typically treated as fixed.1 Indeed, tomany, the very idea of racial mobility will seem like an oxymoron. If race is a characteristic one inherits – we are what we are because ofwhat our biological parents were before us, and their biological parents were before them, and so on – then race can be ascribed at birth and would remain fixed throughout one’s lifetime. A person’s race would never change because there is no way to change one’s biological parents. This is the commonsense understanding of race in the United States, and it has been for several hundred years (...).