In Moneyball, Michael Lewis explores the history of sabermetrics—the practice of using math and statistical analysis to analyze the game of baseball. In the early 2000s, Billy Beane, the general manager of the Oakland Athletics baseball team, and his assistant, Paul DePodesta, came to the conclusion that professional baseball players were evaluated according to a system that often gave a misleading idea of their actual value to a baseball team. With the A’s operating with a smaller financial budget than more well-funded teams, the A’s needed to find an edge that allowed them to acquire value for less than it should cost. With Paul’s help, and building off of the strategies developed by the previous A’s general manager, Sandy Alderson, Billy used sabermetrics to identify players with valuable traits that were overlooked by other general managers and talent scouts, and assemble a team that went on to make the playoffs, and at one point win a record-setting 20 games in a row. As Lewis sees it, the Oakland A’s’ success in 2002 was a major victory for rationality in professional baseball: after many decades of using irrational, arbitrary means to assess players, Billy and Paul used statistics to manage baseball in a more rational, scientific way.
Billy and Paul’s sabermetric style of baseball management rests upon a set of simple, but in some cases controversial, assumptions about the game. Their first major assumption—borrowed from the writing of Bill James, one of the pioneers of the sabermetric approach—is that the more one knows about a ballplayer’s past performance, the more accurately one can predict that player’s future success. This means that, for example, Billy and Paul refrain from drafting high school players for the simple reason that high school players have fewer reliable statistics than older players. Billy and Paul’s second assumption is that statistics are always more reliable than eyewitness testimony when it comes to assessing a player’s value to the game. Their third assumption is that some sports statistics are more important than others. Paul quickly realizes that the most popular statistics for ballplayers, such as batting average (the likelihood of a player getting a hit in a given at-bat), are overrated. Much more important was a player’s on-base percentage (i.e., the probability of a player getting on base via a hit or a walk, and thus not getting out. Put together, Billy and Paul’s sabermetric approach to baseball leads them to draft ballplayers who, in most general managers’ estimation, shouldn’t be on any big-league team. However, Billy and Paul (and sabermetrics) are vindicated when the Oakland A’s go on to win a record number of games in 2002.
The rational, statistical approach to baseball management is not without some drawbacks. As Michael Lewis points out more than once, sabermetrics can be unsympathetic or even heartless: indeed, Billy fires and demotes some players in mid-season simply because their statistics aren’t good and there’s no rational reason to keep them around. On the same note, sabermetrics could be interpreted as dehumanizing: it conceptualizes athletes as combinations of interchangeable numbers whose behavior can be predicted, at least in the long run, with surgical accuracy. At the same time, statistics about how a player has performed can’t always predict how a player will perform. Sometimes, players don’t get along with their teammates, they go through personal crises, have accidents, lose their focus, and experience all kinds of other setbacks that statistical analysis cannot predict. In general, there is a strong element of randomness in baseball. Paul and Billy try to minimize randomness, but they can’t do away with it altogether. In the anticlimactic ending of Moneyball, the Oakland A’s phenomenal 2002 season ends in a playoff loss to a much weaker team, which shows the Achilles heel of sabermetrics: even if sabermetrics can predict a player’s overall success rate, it cannot predict the outcome of a single baseball game, since there’s too much randomness to take into account. In all, it’s important to keep Paul and Billy’s achievements in perspective. They challenge the conventional baseball wisdom, using mathematics to develop a more economic, rational approach to hiring ballplayers. Nevertheless, baseball remains a mysterious and somewhat unpredictable sport.
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Statistics and Rationality Quotes in Moneyball
There was, for starters, the tendency of everyone who actually played the game to generalize wildly from his own experience. People always thought their own experience was typical when it wasn't. There was also a tendency to be overly influenced by a guy's most recent performance: what he did last was not necessarily what he would do next. Thirdly—but not lastly—there was the bias toward what people saw with their own eyes, or thought they had seen. The human mind played tricks on itself when it relied exclusively on what it saw, and every trick it played was a financial opportunity for someone who saw through the illusion to the reality. There was a lot you couldn't see when you watched a baseball game.
"He's the only player in the history of the SEC with three hundred hits and two hundred walks," says Paul, looking up from his computer.
It's what he doesn't say that is interesting … He doesn't explain why walks are important. He doesn't explain that he has gone back and studied which amateur hitters made it to the big leagues, and which did not, and why. He doesn't explain that the important traits in a baseball player were not all equally important. That foot speed, fielding ability, even raw power tended to be dramatically overpriced. That the ability to control the strike zone was the greatest indicator of future success. That the number of walks a hitter drew was the best indicator of whether he understood how to control the strike zone.
The statistics were not merely inadequate; they lied. And the lies they told led the people who ran major league baseball teams to misjudge their players, and mismanage their games. James later reduced his complaint to a sentence: fielding statistics made sense only as numbers, not as language. Language, not numbers, is what interested him. Words, and the meaning they were designed to convey. "When the numbers acquire the significance of language," he later wrote, "they acquire the power to do all of the things which language can do: to become fiction and drama and poetry.”
By the early 1990s it was clear that "sabermetrics,” the search for new baseball knowledge, was an activity that would take place mainly outside of baseball. You could count on one hand the number of "sabermetricians" inside of baseball, and none of them appears to have had much effect. After a while they seemed more like fans who second-guessed the general manager than advisers who influenced decisions. They were forever waving printouts to show how foolish the GM had been not to have taken their advice.
Jeremy Brown, owner of the University of Alabama offensive record books as a catcher, had been so perfectly conditioned by the conventional scouting wisdom that he refused to believe that any major league baseball team could think highly of him.
A revaluation in the stock market has consequences for companies and for money managers. The pieces of paper don't particularly care what you think of their intrinsic value. A revaluation in the market for baseball players resonates in the lives of young men. It was as if a signal had radiated out from the Oakland A’s draft room and sought, laserlike, those guys who for their whole career had seen their accomplishments understood with an asterisk. The footnote at the bottom of the page said, "He’ll never go anywhere because he doesn't look like a big league ballplayer."
The system then carved up what happened in every baseball play into countless tiny, meaningful fragments. Derivatives. "There are all sorts of things that happen in the context of a baseball play," said Armbruster, "that just never got recorded."
The A’s front office realized right away, of course, that they couldn't replace Jason Giambi with another first baseman just like him. There wasn't another first baseman just like him and if there were they couldn't have afforded him and in any case that’s not how they thought about the holes they had to fill. The important thing is not to recreate the individual," Billy Beane would later say. "The important thing is to recreate the aggregate.”
Justice walked a lot. Just a few years ago Justice's ability to wait for pitches he could drive—to not get himself out by swinging at a pitcher's pitch
–had enabled him to hit lots of home runs, too. Much of his power was now gone. His new Oakland teammates witnessed his dissipation up close. After he'd hit a long fly ball, Justice would return to the A’s dugout and say, matter of factly, "That used to be out." There was something morbid about it, like watching a death, play-by-play.
The A’s front office didn't care. They sought only to milk the last few ounces of superior on-base percentage out of David Justice before he expired.
Billy Beane wanted him to hit. Hatteberg told his agent to cut a deal with Oakland: one year with a club option for a second with a base salary of $950,000 plus a few incentive clauses. The moment he signed it, a few days after Christmas, he had a call from Billy Beane, who said how pleased he was to have him in the lineup.
And, oh yes, he'd be playing first base.
In his youth he might have mouthed off. He would certainly have borne a grudge. But he was no longer young; the numbness had long since set in. He thought of himself the way the market thought of him, as an asset to be bought and sold. He'd long ago forgotten whatever it was he was meant to feel.
At length, he penned an article revealing his findings for baseballprospectus.com. Its conclusion: "There is little if any difference among major league pitchers in their ability to prevent hits on balls hit into the field of play.”
This was the character whose behavior was consistent with the way he said he wanted to run his baseball team: rationally. Scientifically. This was the "objective" Billy Beane, the general manager who was certain that "you don't change guys; they are who they are." Who will describe his job as "a soap box derby. You build the car in the beginning of the year and after that all you do is push it down the hill." To this Billy Beane's way of thinking there was no point in meddling with the science experiment … But there is another, less objective Billy Beane … And he allows me to see that the science experiment is messier than the chief scientist usually is willing to admit.
"I made one decision based on money in my life—when I signed with the Mets rather than go to Stanford—and I promised I'd never do it again." After that, Billy confined himself to the usual blather about personal reasons. None of what he said was terribly rational or "objective"—but then, neither was he. Within a week, he was back to scheming how to get the Oakland A’s back to the playoffs, and Paul DePodesta was back to being on his side.
Everybody's laughing at him again. But their laughter has a different tone. It's not the sniggering laughter of the people who made fun of his body. It's something else. He looks out into the gap in left center field. The outfielders are just standing there: they've stopped chasing the ball. The ball's gone. The triple of Jeremy Brown's imagination, in reality, is a home run.
