1. It is believed that MIT graduating Ph.d. students are more likely to stay in academia than those from any other school or field.
2. Across 1977-2011, MIT economists made up 34 percent of the members of the CEA, and Robert Solow supervised one-third of that group.
3. Even in the early days of MIT, Paul Samuelson was not a major thesis advisor, and his students were not so likely to return to MIT as faculty.
4. Out of 35 J.B. Clark medalists until 2012, 47% of them have some affiliation with MIT, either a degree from there or teaching there.
5. As of a few years ago (I am not sure of the exact date), there were 1316 holders of an MIT Ph.d. in economics.
6. In the 2000s, Daron Acemoglu was the most active thesis advisor at MIT.
That is all from “MIT’s Rise to Prominence: Outline of a Collective Biography,” by Andrej Svorenčík. There are various versions of that article here, the jstor version here, and it is reprinted in MIT and the Transformation of American Economics, edited by E. Roy Weintraub.