Doctoral degrees: The disposable academic | The Economist

On finishing a PhD:

In America only 57% of doctoral students will have a PhD ten years after their first date of enrolment. In the humanities, where most students pay for their own PhDs, the figure is 49%. Worse still, whereas in other subject areas students tend to jump ship in the early years, in the humanities they cling like limpets before eventually falling off. And these students started out as the academic cream of the nation. Research at one American university found that those who finish are no cleverer than those who do not. Poor supervision, bad job prospects or lack of money cause them to run out of steam.