The remarkable story of the global movement championing the idea that evidence, not opinions, should guide our decisions Today, more and more people around the globe are using scientific evidence to figure out what works—in health, government and business as well as conservation, schools and parenting. This wasn’t always the case. This book tells the story of the evidence revolution—a worldwide movement that promotes evidence-based thinking—and shows how it can help us all, especially in an age of alternative facts. For many years, most medical advice was based on doctors’ opinions and conventional wisdom, not solid science. Helen Pearson describes how evidence-based medicine swept the world in the 1990s—becoming the predominant form of medicine practiced today—and how the idea that evidence should guide decisions is quietly transforming a host of other fields as well. Do police patrols reduce crime? Do performance appraisals boost job performance? Do welfare programs help the poor?