In 2010, American statistician Nate Silver, who had excelled at using math to predict the results of baseball games and the election of Barack Obama, was asked to do an analysis of the World Cup in South Africa. He predicted that Brazil would be champions. We took 2-1 in the quarter-finals and took sixth place.
There was nothing wrong with Silver’s math, which by the way didn’t even fare worse than other experts: it’s just that football is much harder to model mathematically than other sports. According to researchers at Cornell University in the United States, the favorite team wins only 50% of the time, while this happens 60% of the time in baseball, and almost 70% in basketball or American football.
This is scientifically explained by the Law of Large Numbers, a theorem regarding random events such as coin flips proved in 1713 by Swiss mathematician Jacob Bernoulli. The law states that although the outcome —heads or tails— for each flip is unpredictable, if we repeat it many times it is virtually certain that each side will come out half the time: the probability of having more than 51% heads or tails crowns is very low.
A basketball game consists of a large number of plays in which teams try to score. With each move, success is uncertain, but with repetition, the stronger team ends up prevailing. In football, however, there are few moments susceptible to change the score: it is rare that there are more than a dozen shots on goal. So the result is much more random: the Cornell researchers estimate it to be 50% talent and 50% luck.
Some people think it’s unfair that the best team is subject to losing just because of bad luck. The problem could be “solved”, they say, by changing the rules to increase the number of goals per game, which would reduce the role of chance.
But unpredictability is precisely one of the aspects of football that makes it so passionate: in what other sport could North Macedonia fans enter the stadium with the hope of eliminating four-time champions Italy?
In fact, in sports such as baseball and basketball in the United States, great efforts are made to keep teams balanced and, with that, restore the role of luck!
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It turns out that there are slightly worrying indications that football is becoming more predictable than it used to be. It will be the topic of next week.
