Cubs win the World Series.
Donald Trump wins the White House.
What do those two epochal events have in common? Both were considered highly unlikely. And both happened.
Many fans didn't expect the Cubs to come back from a 3-games-to-1 deficit against the Cleveland Indians. But they knew from data that it was statistically possible: Five teams in history had done just that.
Most Americans probably didn't expect Donald Trump to overcome a polling deficit against Hillary Clinton to win the presidency. And those polls were all but unanimous: The odds against Trump, as those against the Cubs, looked daunting.
But daunting and impossible aren't synonyms.
In the aftermath of the alleged Epic Big Data fail on Election Day, many Americans will judge predictions, projections and premonitions with more skepticism. They've learned an important, even comforting, lesson about the limits of polling and other measures: Big Data is not destiny.
Algorithms are formulas written by humans to take the guesswork out of what other human beings will do under certain circumstances. Will they buy this toothpaste? At what price?
Survey responses to pollsters, consumer buying habits, internet site visits, etc. can be plugged into computer models to suggest people's future behavior. The understandable hope is always that if you start with knowable measurements and crunch them through well-constructed formulas, you'll produce a reliable preview of what will happen.
Computers don't read minds. Nor do pollsters. People don't always say what they think. Or they change their minds. People can be convinced and unconvinced. Some people say one thing but do another. You will never write a program to take into account all those nuances and many others.
To a computer, predicting behavior is an efficient but wisdom-deprived matter of manipulating ones and zeros. But the real world isn't always binary.
"People mistake having a large volume of polling data for eliminating uncertainty," writes Nate Silver of the website FiveThirtyEight.com, one of many prognosticators who whiffed the election call. "It doesn't work that way. Yes, having more polls helps to a degree, by reducing sampling error and by providing for a mix of reasonable methodologies. Therefore, it's better to be ahead in two polls than ahead in one poll, and in 10 polls than in two polls. Before long, however, you start to encounter diminishing returns. Polls tend to replicate one another's mistakes."
Big Data can lead to Big Mistakes. Google Flu Trends, for instance, sought to use data from internet searches to estimate when influenza season would peak and at what level. But it drastically overestimated peak flu levels in the 2012-13 season. That failure "doesn't erase the value of big data," wrote David Lazer of Northeastern University and Ryan Kennedy of the University of Houston in Wired magazine. "What it does do is highlight a number of problematic practices in its use — what we like to call 'big data hubris.'"
We'd say that many alleged political pros suffered a serious case of that affliction before voters set them straight Nov. 8.
Should we toss out data and rely only on experience, or on anecdotes, or on what we hear (true or false) from people with whom we agree?
That would be a dangerous overreaction to the election flub. If people believe the data cannot be trusted, they may turn instead to "trusting anecdotes from friends, family and tribe," political blogger Erick Erickson writes in The New York Times. "Policies will be based on what people think are good ideas, not what data show. This will potentially further divide the country and further segment an already divided nation," he warns, aptly.
Humans embrace Big Data — more than they would if it were more accurately billed as Big Guesses or Big Evidence-based Hunches — because we live in an unpredictable universe that is often capricious. People feel comforted when they think they know what is going to happen. They see patterns in random chance. They purge from their thoughts the reality that a 74 percent chance of victory is a 26 percent chance of defeat. Superstition endures.
Reality is elastic. Every moment brings new possibilities. That's what makes life intriguing.
Many predictions proved wrong on Election Day.
As did many predictions when the Cubs were down 3-games-to-1.
That's why we vote.
That's why we play the games.
Copyright Chicago Tribune. Distributed by The Associated Press.