Calling Bullshit: The Art of Skepticism in a Data-Driven World

by Carl T. Bergstrom

OUR WORLD IS THOROUGHLY QUANTIFIED. Everything is counted, measured, analyzed, and assessed. Internet companies track us around the Web and use algorithms to predict what we will buy. Smartphones count our steps, measure our calls, and trace our movements throughout the day. “Smart appliances” monitor how we use them and learn more about our daily routines than we might care to realize. Implanted medical devices collect a continuous stream of data from patients and watch for danger signs in real time. During service visits, our cars upload data about their performance and about our driving habits. Arrays of sensors and cameras laid out across our cities monitor everything from traffic to air quality to the identities of passersby. Instead of collecting data about what people do through costly studies and surveys, companies let people come to them—and then record what those consumers do. Facebook knows whom we know; Google knows what we want to know. Uber knows where we want to go; Amazon knows what we want to buy. Match knows whom we want to marry; Tinder knows whom we want to be swiped by. Data can help us understand the world based upon hard evidence, but hard numbers are a lot softer than one might think. It’s like the old joke: A mathematician, an engineer, and an accountant are applying for a job. They are led to the interview room and given a math quiz. The first problem is a warm-up: What is 2 + 2? The mathematician rolls her eyes, writes the numeral 4, and moves on...