The statistics that drive our big-picture economic thinking — GDP, unemployment figures, and inflation rates, among others — have come to be regarded as nearly sacrosanct. Investors, policymakers, and everyday consumers rely on them to make decisions trivial and earthshaking alike, often measured in trillions of dollars. Zachary Karabell, in his book The Leading Indicators: A Short History of the Numbers That Rule Our World, traces the history of these numbers and questions how useful they actually are.