Cathy O'Neil, data scientist and author of Weapons of Math Destruction talks with EconTalk host Russ Roberts about the ideas in her book. O'Neil argues that the commercial application of big data often harms individuals in unknown ways. She argues that the poor are particularly vulnerable to exploitation. Examples discussed include prison sentencing, college rankings, evaluations of teachers, and targeted advertising. O'Neil argues for more transparency and ethical standards when using data.