We investigate divisions within the citation network in economics using citation data between 1990 and 2010. We consider all partitions of top institutions into two equal-sized clusters, and pick the one that minimizes cross-cluster citations. The strongest division is much stronger than could be expected to be found under idiosyncratic citation patterns, and is consistent with the reputed freshwater/saltwater division in macroeconomics. The division is stable over time, but varies across the fields of economics.
Or put it this way:
The likelihood of citing a paper by an author from another university in the same cluster is about 16% higher than the likelihood of citing a paper by an author from the other cluster.
Oddly, Northwestern and Penn are in the freshwater cluster of citations. Yale and Michigan are the only two schools whose cluster changes with the specification.
Berkeley and MIT have the saltiest taste, while Minnesota and Rochester are the freshest of the fresh. Chicago has a more neutral set of citation practices than many economists (not I) might think. Chicago cites saltwater school papers at a higher rate than the general average, nonetheless Chicago ends up strongly in the freshwater camp because it is cited so much by other freshwater schools, and not so much by the saltwater schools. A cynic might wonder if the Chicago economists are more open-minded than their critics, and I must confess that is consistent with my own anecdotal experience.
By the way, all this corresponds to hiring placement data. Sadly, academic hiring is more clustered across camps of schools than is the case for…comparative literature. If you are wondering, the saltiest Fed branch is in Boston, the least salty in Richmond.
Addendum: Bob Hall directs my attention to his posting: “In a 1976 paper, I introduced the distinction between fresh-water and salt-water economists. Bloggers using these terms are asked to contribute $1 to a fund that sends graduate students to MIT for one year and to the University of Minnesota for a second year.”