Why did the A’s stop winning? Scott has the answer

I have been watching Moneyball. It is a great movie, but unlike Scott Sumner and my wife I have actually no clue about movies. However, economics play a huge role in this movie. So that surely made me interested. It is of course very different from Michael Lewis’ excellent book Moneyball, but it is close enough to be an interesting movie even to nerdy economists like myself.

If I was not blogging about monetary policy and theory then there is a good chance I would be blogging about what Bob Tollison called Sportometrics – the economics of sports. It combines two things I love – sports and economics. But why bring Moneyball into a discussion about money and markets? Well, because the story of the Oakland A’s is a pretty good illustration that Scott Sumner is right about the Efficient Market Hypothesis (EMH) – even when it comes to the market of baseball players. So bare with me…

Any American male knows the story about the Oakland A’s but for the rest of you let me just re-tell the story Michael Lewis tells in Moneyball.

The story about the Oakland A’s is the story about the A’s’ general manager Billy Beane who had the view that the market was under-pricing certain skills among baseball players. By investing in players with these under-priced skills he could get a team, which would be more “productivity” than if he had not acknowledged this under-pricing. Furthermore as other teams did not acknowledge this he would increase his chances of winning even against teams with more resources. It’s a beautiful story – especially because theory worked. At least that is how it looked. In the early 2000s the Oakland A’s had much better results than should have been expected given the fact that the A’s was one the teams in the with the lowest budgets in the league. The thesis in Moneyball is that that was possible exactly because Billy Beane consistently used of Sabermetrics – the economics of Baseball.

Whether Lewis’ thesis correct or not is of course debatable, but it is a fact that the Oakland A’s clearly outperformed in this period. However, after Moneyball was published in 2003 the fortune of the Oakland A’s has changed. The A’s has not since then been a consistent “outperformer”. So what happened? Well, Billy Beane was been beaten by his own success and EMH!

Basically Billy Beane was a speculator. He saw a mis-pricing in the market and he speculated by selling overvalued players and buying undervalued players. However, as his success became known – among other things through Lewis’ book – other teams realised that they also could increase their winning chances by applying similar methods. That pushed up the price of undervalued players and the price of overvalued player was pushed down. The market for baseball players simply became (more?) efficient. At least that is the empirical result demonstrated in a 2005-paper An Economic Evaluation of the Moneyball Hypothesisby Jahn K. Hakes and Raymond D. Sauer. Here is the abstract:

Michael Lewis’s book, Moneyball, is the story of an innovative manager who exploits an inefficiency in baseball’s labor market over a prolonged period of time. We evaluate this claim by applying standard econometric procedures to data on player productivity and compensation from 1999 to 2004. These methods support Lewis’s argument that the valuation of different skills was inefficient in the early part of this period, and that this was profitably exploited by managers with the ability to generate and interpret statistical knowledge. This knowledge became increasingly dispersed across baseball teams during this period. Consistent with Lewis’s story and economic reasoning, the spread of this knowledge is associated with the market correcting the original mis-pricing.”

Isn’t it beautiful? The market is not efficient to beginning with, but a speculator comes in and via the price system ensures that the market becomes efficient. This is EMH applied to the baseball market. Hence, if a market like the baseball market, which surely is about a lot more than making money can be described just remotely as efficient why should we not think that the financial markets are efficient? In the financial markets there is not one Billy Beane, but millions of Billy Beanes.

Every bank, every hedgefund and every pension fund in the world employ Billy Beane-types – I am one of them myself – to try to find mis-pricing in the financial markets. We (all the Billy Beanes in the financial markets) are using all kind of different methods – some of them very colourful like technical analysis – but the aggregated result is that the markets are becoming more efficient.

Like Billy Bean the speculators in the financial markets are constantly scanning the markets for mis-priced assets and they are constantly looking for new methods to forecast the market prices. So why should the financial markets be less efficient than the baseball market? I think Scott is right – EMH is a pretty good description of the financial markets or rather I haven’t seen any other general theory that works better across asset classes.

——————–

PS there is of course also the possibility that Billy Beane was just lucky“The sample is simply not big enough” (“Peter Brand” in the movie about why his theory initially did not work).

PPS  In Moneyball the movie the term “Winning streak” is used. That is a bit of a turn off for anybody who has studied a bit of sportometrics. There is not such a thing as a winning streak or a “hot hand” – at least that can not be proved empirically.

PPPS Moneyball is not really about Billy Beane, but rather about Paul DePodesta. In the Moneyball Paul DePodesta is renamed Peter Brand.

PPPPS I have no clue about baseball and find it rather boring…that must be the ultimate disclaimer.

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5 Comments

  1. Interesting post – watched “Moneyball” in the plane to Bangkok (haven’t read the book).

    In the same context I would recommend “Scorecasting” by Jon Wertheim (journalist) and Tobias Moskowitz. Moneyball and Freakonomics in one.

    Reply
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