The Minnesota Twins are my favorite baseball team. So I was ecstatic when, back in June, they went on a nine game winning streak to come within a few games of first place. But I was also confused: they were plagued by injuries, AAA players filled half their roster, they weren’t scoring very many runs and they weren’t pitching particularly well. How was it, I asked, that they almost pulled off the magical "worst-to-first"?
ESPN and Sports Illustrated commentators had their explanations as usual, ranging from better coaching, to more focus by the players, to warmer June weather. But being the skeptic I am, I wasn’t buying any of this nonsense. Instead, I recalled the famous "hot hand" study (pdf) done by psychologists Tom Gilovich, Amos Tversky and Robert Vallone. After pouring through shooting records of the Philadelphia 76ers 1980-1981 season, they found that the chance a basketball player has of making a shot is actually unrelated to the outcome of his previous shot. In Gilovich’s words, "a player’s performance on a given shot is independent of his performance on previous shots."
Similar results were found with baseball teams and baseball players. Michigan State University psychologist Gordon Wood demonstrated that the probability of an MLB team winning after a win or losing after a loss was fifty percent after analyzing the outcomes of all 1988 Major League Baseball games. Likewise, Indiana University statistician Christian Albright found (pdf) that batters, "[do] not differ significantly from what would be expected under a model of randomness," after analyzing statistics from Major League players through four seasons. In short, an MLB game and at bat are, like the outcome of a basketball shot, unaffected by past performance. This means that the Twins won nine in a row because, well, inherent in a string of 162 baseball games are streaks. The problem is that we do a really bad job of interpreting these streaks.
Our tendency to "see" streaks plays to a bigger point: our intuitions about sports are typically way off the mark.
This is highlighted in Scorecasting, a wonderful new book by University of Chicago finance professor Tobias Moskowitz and Sport Illustrated writer Jon Wertheim. The book does to sports what Freakonomics did to economics. That is, it "confronts conventional sports wisdom." They ask, for example: Is it really preferable to punt on fourth down rather than go for it? To try to achieve the highest available spot in the draft? Is there an I in team? Does defense truly win championships? And, of course, is it smart to keep feeding the teammate with the hot hand?
We know that the hot hand is a myth, so let’s take fourth downs.
For that, consider a study (pdf) done a few years ago by an economist David Romer. Romer analyzed every fourth down that occurred in the first quarter of every NFL game from 1998 to 2000. After considering several variables Romer developed a mathematical model that gave the probability of successful converting fourth downs and kicking a field goal depending on position and circumstance. Then, he compared his model with what actually happened. He concluded that, "the behavior of National Football League teams on fourth downs departs systematically from the behavior that would maximize their chances of winning." In other words, it is usually better to go for it on fourth down, and coaches do a really good job of not doing this.
Studies like Romer’s abound. It turns out that if you run the numbers, coaches and managers are the kings and queens of making non-optimal decisions. With the exception of Kevin Kelley who categorically opposes punts and usually goes for the onside kick (by the way, he has won multiple state championships as head football coach of Pulaski Academy in Little Rock Arkansas), Billy Beane of Moneyball fame and those who consider sabermetrics, coaches and managers are slow to adapt studies like Romer’s into their play books.
Why would anyone not adjust their game plans in accordance with data that would allow them to choose optimally? Why would you ignore information that could help your team succeed? Why is it, in other words, that when Red Auerbach, long time coach of the Boston Celtics, heard about Gilovich’s "hot hand" study he responded, "so he made a study… I couldn’t care less."
The short answer is that coaches and managers are like all of us: they only look for what confirms their intuitions and ignore what contradictions their intuitions, what psychologists call confirmation bias - a vastly interesting cognitive tendency I have written about before. Confirmation bias helps explain a lot. It’s the Republican who only watches Fox or the Democrat who only watches MSNBC; it’s the lady who sees Mary in toast or the creationist who sees fossils as evidence of God; it’s the grad student who can’t see any flaws in his work or the professor who only looks for evidence that supports her study. We automatically see the world as we want to, not how it is.
In addition to confirmation bias, there’s motivated reasoning, confirmation biases evil twin. Motivated reasoning describes our propensity to scrutinize ideas that oppose our intuitions less than ideas that support our intuitions. My favorite study (pdf) that illustrates motivated reasoning comes from Ziva Kunda. It goes like this. Kunda brought participants into a room and had them play a game. Before they started they watched two other people play the game, one who was far superior (and actually a confederate). Here was the catch: Kunda told half the participants that the expert player would be their teammate and the other half that he would be their opponent. Kunda found that the participants lined up to play with the expert praised his skills while those lined up to play against the expert dismissed his skills and labeled him as lucky.
I hope you can see where I am going with this. When you consider confirmation bias and motivated reasoning, it is easy to understand how a coach or manager would stick to their play books even in the face of data that overwhelmingly shows their strategies to be non-optimal. Being bound by the tendency to only notice what fits with our beliefs (confirmation bias), and having the propensity to scrutinize ideas more when they run contrary to our beliefs (motivated reasoning) is a deadly poison for optimal decision making.
Don’t get too comfortable. You – the fan - aren’t exempt. According to NYU professor of psychology Gary Marcus, who I recently spoke with:
"Fans are subject to motivated reasoning, too. An executive at a major sports league once told me about a study his league did in which fans watched instant replays from controversial plays, and had to judge whether the refs had made valid calls. People were vastly more likely to think that the ref made the right call when the call favored the home team - even though the games were from an earlier season, and it was obviously too late to change anything. Human beings are built to enjoy being "right", and it often distorts our perception."
This helps explain why fans can look at the same statistics, the same standings and the same plays and come to entirely differently conclusions.
And then there are the commentators.
When it comes to analyzing plays and calling games, they are cognitive disasters. Along with confirmation bias and motivated reasoning, they exemplify what Nassim Taleb calls the narrative fallacy. The narrative fallacy describes our "limited ability to look at sequences of facts without weaving an explanation into them, or, equivalently, forcing a logical link, and arrow of relationship, upon them." For example, if the Twins win a game, commentators may point to good pitching, good hitting or good managerial decisions to explain why they won. When they do this they are creating the sense that they understand why the Twins won. This is an illusion. Their explanations are mere post hoc stories that add silly irrelevant facts just to garner more views and increase entertainment. The only fact of the matter about the Twins winning is that they scored more runs than the other team.
They also epitomize the conjunction fallacy, another cognitive bias that describes our tendency to think that, "the probability of any event A and any other event B occurring together has to be less likely than (or equal to) the probability of event A by itself." Here is the classic Kahneman and Tversky example:
Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.
Which is more probable?
1) Linda is a bank teller.
2) Linda is a bank teller and is active in the feminist movement.
If you are like 85% of people, you chose option two even though there is a higher probability that option one is more likely because there are fewer conjunctions; counter-intuitive but it’s true. How do sports-casters commit this error?
During big games or plays they often declare something like this: "Tonight’s game saw the first no-hitter thrown by a lefty pitcher during the month of April." Statements like this give the viewers a sense that what they are watching is rare and unique. This is also an illusion. Again, it’s commentators adding silly irrelevant pieces of information (e.g., lefty or April) to garner more views and increase entertainment. All the while, it’s just another game.
Don’t waste your time calling them out on their errors; confirmation bias and motivated reasoning are robust biases that do an excellent job of narrowing people’s minds; once the narrowing begins, it’s nearly impossible to change people’s minds.
I’m making a simple point. When it comes to sports, data > intuition. Yet, coaches, managers, fans and commentators alike continue to go with their guts, especially when it comes to a team or player that is close to their hearts. If they want to decide optimally or speak about their beloved team or player with slightly more intelligence they should turn off their cognitive biases and look at the data. Trying to persuade someone to change a strategy, root for another team or consider why the sports team from your area is superior to the sports team from their area is not unlike trying to persuade a Republican that Obama is a good President or an atheist that God exists. It’s just not going to happen.
I’m sad to report that the Twins are currently 29 games out of first place. If manager Ron Gardenhire is smart, he will ignore his intuitions to try and understand how data can help his team in 2012. If I’m smart, I’ll mind my cognitive biases so I can actually have an informed discussion about sports.