ADAM KUCHARSKI DIDN’T expect to publish a book about contagion in the middle of a global pandemic. But consider him less surprised than the rest of us. “In my field we always have the next pandemic on the radar,” he says. Kucharski, an epidemiologist at the London School of Hygiene and Tropical Medicine, is a mathematician by training. He uses data and models to predict how disease outbreaks will progress.
His new book, The Rules of Contagion: Why Things Spread—and Why They Stop, lays out those tools and how they can be applied to other parts of life. Think methods to predict how panic might course through the global financial system, or how bad information is transmitted on Facebook. But most important, Kucharski says, is what he calls “epidemiological thinking.” That’s a mindset for dealing with incomplete information, as infectious-disease researchers must when they encounter a novel, fast-moving pathogen. Sometimes you might make bad assumptions, and your models might make predictions that never come to pass. But in a crisis, coming up with a hypothesis, even if it’s a rough one, is often the only way to get people to act.