Something that wasn&#x27;t mentioned here: a Ph.D. in the US is a great way to increase your chances for an offer for professorship back home in Europe (or anywhere, really). That will skew the number towards people who fully intend to leave after getting their Ph.D. as naturally US naturals can derive no such benefit. In fact, if we imagine the opposite holds, they might well be penalized for getting their Ph.D. at a US university.