Greg Mankiw's discussant comments from a paper presented at the ASSA meetings contain a lot of wisdom.
What I think many deans of gradual studies have trouble with is successfully explaining differences across fields in completion rates and time to degree. They see that economics has a lower completion rate than, say, history and they are puzzled. But they should not be puzzled. It is all about opportunity costs as well as, to some extent, differences in fields in the extent to which doctoral study represents consumption rather than investment in human capital.
I am inclined to like Greg's suggestion about MA programs. In Canada, it is the norm for students to do an MA before starting a doctoral program, and the better MA programs, like the ones at Queen's and UBC, manage to do a good job of serving two aims. First, they provide professional training to students who will stop with the MA and take jobs in the government or the private sector. Second, they provide a lot of information to students pondering whether or not to get a doctorate. Whether this information provision function, and the selection it induces, leads to measurably higher completion rates in Canadian economics doctoral programs would be interesting to study. A side benefit of doing an MA first is that the first year of the doctoral program is a bit less stressful. At least, the Canadians in my class at Chicago, who had already at least seen some of the first year material in their MA programs, seemed a bit less stressed out.
It's really quite easy.
1 year ago