I've written about the evils of corporate hierarchy. Robert L. Sutton's new book, "Good Boss. Bad Boss: How to Be the Best . . . and Learn from the Worst" provides fresh evidence that hierarchy harms. He talks about a study of drug treatment errors in hospital nursing units. The most efficient and safest units reported 10 times more drug errors than the least efficient and unsafe units. Yes, you read that right. Sutton writes: "This tenfold difference in reported errors was due to psychological safety, not the actual error rate. Nurses with good bosses felt safe to admit mistakes, nurses with bad bosses avoided reporting errors because doing so provoked humiliation and retaliation." My take: You can't fix what you don't know is broken, and you won't know what's broken unless an employee tells you. A candid and transparent culture makes a manager stronger, not weaker.