From a profile of Judge Diane Wood in the New York Times:

Mr. Obama has talked about the virtues of selecting a justice with broad personal and political experience. Judge Wood is, however, largely a creature of the elite slice of the law that revolves around law schools and federal courts. Her daughter, Kathryn Hutchinson, once said that on family road trips, the children did not ask, "Which state are we in?" but rather, referring to the 12 regional courts of appeals, "Which circuit are we in?"