What Statistics Can and Can’t Tell Us About Ourselves | The New Yorker
▻https://www.newyorker.com/magazine/2019/09/09/what-statistics-can-and-cant-tell-us-about-ourselves
In some ways, this is what you would expect from any large, disordered system. Think about the predictable and quantifiable way that gases behave. It might be impossible to trace the movement of each individual gas molecule, but the uncertainty and disorder at the molecular level wash out when you look at the bigger picture. Similarly, larger regularities emerge from our individually unpredictable lives. It’s almost as though we woke up each morning with a chance, that day, of becoming a murderer, causing a car accident, deciding to propose to our partner, being fired from our job. “An assumption of ‘chance’ encapsulates all the inevitable unpredictability in the world,” Spiegelhalter writes.
But it’s one thing when your aim is to speak in general terms about who we are together, as a collective entity. The trouble comes when you try to go the other way—to learn something about us as individuals from how we behave as a collective. And, of course, those answers are often the ones we most want.
The dangers of making individual predictions from our collective characteristics were aptly demonstrated in a deal struck by the French lawyer André-François Raffray in 1965. He agreed to pay a ninety-year-old woman twenty-five hundred francs every month until her death, whereupon he would take possession of her apartment in Arles.
At the time, the average life expectancy of French women was 74.5 years, and Raffray, then forty-seven, no doubt thought he’d negotiated himself an auspicious contract. Unluckily for him, as Bill Bryson recounts in his new book, “The Body,” the woman was Jeanne Calment, who went on to become the oldest person on record. She survived for thirty-two years after their deal was signed, outliving Raffray, who died at seventy-seven. By then, he had paid more than twice the market value for an apartment he would never live in.