Friday, February 27, 2015

I was about to slam Krugman for ignoring meaningful counter-examples...

I generally like Paul Krugman a great deal, partially because I have a high tolerance for quality snark and partially because... well, let's save that for later. Sometimes though, for lack of a better description, writes like an economist. By this I (somewhat unfairly) mean that he is occasionally too quick to embrace the sweeping and aesthetically pleasing theory that collapses under scrutiny. I have mainly noticed this trend when he ventures out of econ or when he is summarizing the work of colleagues.

Recent case in point (or so I thought).
[Sherwin] Rosen’s argument, more than 30 years ago, was that technology was leading to sharp increases in inequality among performers of any kind, because the reach of talented individuals was vastly increased by mass media. Once upon a time, he said, all comedians had to entertain live audiences in the Borscht Belt; some drew bigger, better-paying crowds than others, but there were limits to the number of people one comic could reach, and hence limits on the disparity in comedian incomes. In modern times, however, an especially funny guy can reach millions on TV; an especially talented band can sell records around the world; hence the emergence of a skewed income distribution with huge rewards for a few.
There is undoubtedly some truth to this, but there are huge counter-examples as well, and substantial parts of the entertainment industry where the hypothesized relationships don't hold at all. I was all set to skewer Krugman over these problems when he had to go and say this:
But the more I look into this, the less I think this story works, at least for music.
He then goes on to show how the theory breaks down, particularly when placed in the context of the general economy.

Here's my favorite example.
But are the big incomes of music superstars something new, or at least a late 20th-century development? Well, let’s take an example where there are pretty good numbers: Jenny Lind, the famous soprano, who toured America from 1850 to 1852.

Tickets at Lind’s first concert sold for an average of about 6 dollars, which seems to have been more or less typical during the tour. Adjusting for inflation, that’s the equivalent of around $180 today, which isn’t too shabby (a lot of the indie concerts I go to are $15-20, although they also make money on beer). But you also want to bear in mind that real incomes and wages were much lower, so that these were actually huge ticket prices relative to typical incomes.

Overall, Lind was paid about $350,000 for 93 concerts, or a bit less than $4,000 a concert. If we adjust for the rise in GDP per capita since then, this was the equivalent of around $2 million a concert today. In other words, to a first approximation Jenny Lind = Taylor Swift. And this was in an era not only without recordings, but without amplification, so that the size of audiences was limited by the acoustics of the halls and the performer’s voice projection.
Which brings me around to that other reason I like Krugman.

I believe it was in one of the plausible reasoning books that George Pólya observed that, as a general principle, if you gave most people a rule they would usually start trying to think of examples; if you gave a mathematician a rule, he or she would generally start trying to think of exceptions.

At the risk of making a sweeping statement as part of an attack on sweeping statements, one of my biggest problems with economist as statistician-at-large trend (see Levitt et al.) is that so few of them think like one of Pólya's mathematicians. Krugman, for all his other flaws, is the kind of writer who tends to notice exceptions.

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