Justin Lahart at the Wall Street Journal suggests a new party game for economists (or at least something to keep you awake if a conference gets dull): Six Degrees of Joe Stiglitz. He’s suggesting the econ version of the Paul Erdos number in math:
If you drew a diagram linking different mathematicians, many of the lines would cross at Erdos. That’s given rise to what’s known as an Erdos number. People who collaborated directly with Erdos have an Erdos number of one. People who collaborated with those collaborators have an Erdos number of two. And so on. Erdos, who died in 1996, has an Erdos number of zero.
Why choose Stiglitz? Well, Stiglitz himself has an Erdos number of four, which means that any economist’s Erdos number is at least as low as their Stiglitz number, plus four. But more to the point, Stiglitz has coauthored broadly and written across many fields, so is arguably the most Erdos-like figure in modern economics.
I’ll bite: My Stiglitz number is three, and I can get there at least three different ways:
Stiglitz-Diamond–Blanchard-Wolfers, Stiglitz-Atkinson–Leigh-Wolfers, or Stiglitz-Blinder–Reis-Wolfers.
Steve Levitt is also a three: Stiglitz-Sachs–Poterba-Levitt, and so Steve endows both Stephen Dubner and Sudhir Venkatesh with a four.
Dan Hamermesh has written so many papers that it is hard to know, but I’m guessing he’s also a three: Stiglitz-Azariadis–Drazen-Hamermesh.
Among Freakonomics bloggers, Ian Ayres has the lowest Stiglitz number at two: Stiglitz-Nalebuff-Ayres, or Stiglitz-Edlin-Ayres. (And Ayres is also a secondary reason for Levitt’s three.)
My guess is that some of the key links (people with a Stiglitz number of one) will turn out to be: Aghion, Akerlof, Arnott, Atkinson, Azariadis, Basu, Blinder, Boadway, Boskin, Brock, Cass, Dasgupta, Diamond, Dixit, Easterly, Eaton, Edlin, Frydman, Fudenberg, Furman, Gilbert, Greenwald, Grossman, Heal, Hellman, Hosios, Jaffee, Nalebuff, Newberry, Niskanen, Orszag, Przeworski, Radner, Rothschild, Sachs, Sah, Salop, Shapiro, Shell, Solow, Stern, Stockman, Tirole, Walsh, Weiss, and Woodford — just to list the first couple of dozen among the multitude of people boasting a Stiglitz number of one.
And when we are done playing the Six Degrees of Joseph Stiglitz, let me suggest that for subsequent rounds we try Six Degrees of: Larry Summers, Gary Becker, Milton Friedman, Kenneth Arrow, Paul Samuelson, John Maynard Keynes, and Alfred Marshall.
These get much harder with earlier generations of economists, because team production of research is increasing.