How Are Economists Connected?
The National Bureau of Economic Research, an organization of top economists that serves as a sort of clearinghouse for new research papers, counts nearly 1,400 members. Their interests vary widely, but upon joining the NBER, they sign up for research programs that represent their favored topics.
The NBER has 20 such programs, and economists usually sign up for one or two, although some sign up for more. (Twelve economists are signed up for five programs. Andrei Shleifer is the only one signed up for six.) As a result, we have over 700 connections between topics.
With so many members signing up for different combinations of programs, the NBER's member interest list gives a picture into the field. Not only can it tell us what fields are popular and unpopular, but also, it shows us what combinations are comparatively more or less common -- a window, perhaps, into the connections economists draw within their own field.
So I scraped the NBER's member list and got started. (As always, my data set is available here.)
The first metric I looked at was the correlation of registrations, as you can see in the matrix below. (Click it to enlarge.) You should interpret a significantly positive cell as "economists often put these topics together," a cell with a value near zero as "there are no strong connections between these two topics," and a significantly negative cell as "economists tend not to put these two topics together."
Some things immediately popped out at me. NBER members that were interested in monetary economics, for instance, also tend to be interested in economic fluctuations and growth. Those that are interested in the economics of education also tend to do work on labor economics. Both of those connections make a great deal of sense!
The areas where economists seem to pick and choose are also fascinating. Labor economists seem to dislike asset pricing. Those interested by economic fluctuations and growth stay away from education. And so on.