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!That second paragraph strikes me as too strong. It's not so much that people who do labor economics dislike asset pricing as it is that the nationally representative surveys providing material for regression analysis contain a lot of correlations among income, health, and education, but not a lot that can be cross-referenced to the security price data. For the same reason, industrial organization skills transfer more readily to environmental and energy topics (hi!) than they do to, say, the effect of obesity on childhood depression. Likewise, the state of the art in the microfoundations of human capital formation doesn't aggregate up easily.
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.
HARVESTING AN ECONOMY OF SCOPE.
Evan Soltas constructs a shared-interest crosstabulation based on the declared interests of economists affiliated with the National Bureau of Economic Research.