Dan is in good form here discussing common maladies in political science dissertation prospectuses.
Awkward dissertation proposals tend to take a somewhat different form in economics, at least in my experience. Usually the student has fallen in love not with some particular author but with some particular insight that, while it might make a great second or third contribution to a paper, is not really able to sustain a paper all by its lonesome, or, if it is, that paper will end up in an obscure journal, rather than in (at worst) a top field journal, which is what students should be aiming for with their job market papers (which in economics are the lead essay in a "three essays on stuff" dissertation).
Who was my favorite student this term?
7 months ago