Solving problems like poverty, education inequality or discrimination require policy interventions that can scale, but they rarely do. Why do some scale, while others have little success? It's not luck, it's not skill, it's actually a scientific method—at least, that's how Prof. John List describes it. A world-renowned economist at the University of Chicago, List has helped scale some big policies and technologies as a former White House chief economist and the chief economist for both Uber and Lyft. Through his experience, he's observed a thing or two about what not to do. In his new book, The Voltage Effect: How To Make Good Ideas Great And Great Ideas Scale, List lays out five key factors that people should consider when thinking through any idea, policy or product. He explains how shifting from policy-based evidence to evidence-based policy can solve some of the world’s more pressing issues.