What if the thing we call "talent" is grotesquely overrated? And what if deliberate practice is the secret to excellence? Those are the claims of the research psychologist Anders Ericsson, who has been studying the science of expertise for decades. He tells us everything he's learned.

By some estimates, medical error is the third-leading cause of death in the U.S. How can that be? And what's to be done? Our third and final episode in this series offers some encouraging answers.