Saturday, November 15, 2008

How to win the Nobel prize by a whisker

Tim Harford writes in FT few fascinating analytics see some of those below: 

“The Nobel memorial prize in economics is typically awarded to researchers who have jointly advanced some important method or idea. When the 2008 prize was awarded to Paul Krugman alone, for his contributions to trade theory and economic geography, other candidates who might have shared the prize – but didn’t – must have counted themselves one small step further away from receiving the call from Stockholm.    

Among them are Jagdish Bhagwati, Krugman’s teacher and champion, and a giant in the field of international trade; and Elhanan Helpman, who wrote an influential book with Krugman on the new trade theory. 

Economies of scale push towards larger and larger companies. Logically, a monopolist should be the lower-cost provider. The tension between economies of scale and competition is obvious. 

Yet while obvious, it is hard to model mathematically in a useful way. Dixit and Stiglitz resolved the problem by observing that consumers have a taste for variety as well as a taste for low prices. In the market for cars, for instance, Volvos compete with Fords and Ferraris. It would be cheaper if there was only one model of car; it would be nicer if there was an infinite variety. Somewhere in the middle is the equilibrium where economies of scale are balanced by customers’ desire for variety. 

The elegant mathematics of the Dixit-Stiglitz model was new, even if the tension it described was as old as Smith’s Wealth of Nations. Krugman described it is as “beautiful”. It quickly became a workhorse, pulling economists to new frontiers of trade theory, growth theory and economic geography. Dixit later said he and Stiglitz had not realised the model would have so many uses – “obviously, otherwise we would have written all those subsequent papers ourselves!” 

That is typically generous of a man who has often praised others, especially Krugman. He once told young economists that a good place to have ideas was in front of the shaving mirror. Krugman has a beard. Imagine, quipped Dixit, how much he could have achieved if he shaved!” 

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