In 1987, on a summer Sunday morning, 300,000 people crammed onto the central span of San Francisco’s Golden Gate Bridge—and came perilously close to participating in the largest accident in American history. The bridge’s engineers had made copious calculations and had designed it to sway nearly 28 feet and shoulder the burden of hundreds of vehicles. But nobody had ever predicted that a gigantic crowd of pedestrians, attracted by the 50th anniversary of its opening, would be stuck between its towering pylons unable to move in any direction. As a result, the bridge flattened out and came within whiskers of straining every last fiber of its vermilion superstructure.
The consequences of faulty data, wonky forecasts, ill-conceived opinions, loose predictions, incorrect assumptions and, in the case of the Golden Gate Bridge, an improbable event form the backbone of Nate Silver’s absorbing new book, The Signal and the Noise: Why Most Predictions Fail but Some Don’t. This book, written by the voice behind the popular election forecasting blog, FiveThirtyEight, now licensed by the New York Times, is a reminder that while data doesn’t lie, it does allow people to deceive themselves and others. In some cases it’s a question of the bigger the data, the grander the deception.
These days our entire lives revolve around predictions. Government departments project the cost of health exchanges, the rate of economic growth, next year’s crop yields, the future birth rate and the arms buildup of unfriendly countries. Websites and retailers anticipate what we want to find and buy; oil companies gauge the best sites for drilling; pharmaceutical companies assess the probable efficacy of molecules on a disease; while, in the background, the bobble-heads on television incessantly spew out largely irrelevant and inaccurate forecasts. In the meantime, we busy ourselves with personal projections. How long will our commute take? When will the turkey be golden? How much will the price of a stock rise? What will the future value be of a law degree?
Some of these forecasts are surprisingly accurate while others are shockingly dismal. Silver, who has become the Woody Allen of statisticians, explains the reasons. Like many others, the 34-year-old Silver became fascinated with numbers because of a boyhood devotion to baseball. Unlike his peers, Silver – after a brief and frustrating spell as a consultant – instinctively returned to the challenges of numbers. He took up internet poker (only to eventually discover that the odds were not in his favor) and, also started to unravel the riddles presented by data.
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