Q: How'd you get started on this book? A: A few years ago, I did a front page story for The Wall Street Journal on the safety record of an unlikely group of mistake-makers: anesthesiologists. For a long time, they had a terrible record in the operating room; patients turned blue and suffocated right in front of them. Sometimes, flammable gases ignited and blew up. It was terrible. These mistakes were often written off as "human error"—meaning there was nothing that could be done. But when the anesthesiologists got serious about eliminating these errors, they found out they found out there was something that could be done. In fact, there were a lot of things that could be done. And I thought: huh, they're on to something. Q: How long did it take you to write the book? A: Between two and three years. Q: What's the most important thing you learned? A: Three words: perception is economical. Q: Why is this so important? A: Because we don't think our perception is economical; we think it's perfect. When we look at something, we think we see everything. But we don't. Same with memory: we might think we remember everything, especially commonly encountered things like the words to the National Anthem, or the details on the surface of a penny—but we don't. Our brains are wired to give us the most bang for the buck; they strip out all sorts of stuff that seems unimportant at the time. But we don't know what's been stripped out. One of the consequences of this is that we tend to be overconfident about the things we think we do know. And overconfidence is a huge cause of human error. Q: How's that? A: Well, in part, because we hate, hate, hate to think of ourselves as average—or, God forbid, below average. So we do things at which we repeatedly fail because we overestimate our abilities. Q: Can you cite an example? A: Sure: losing weight. One of the most successful weight-loss companies in the U.S. is NutriSystem. You've probably seen their ads on TV—they feature celebrities like former quarterback Dan Marino, who says he lost 22 pounds. Anyway, if you look closely at the ads, you'll notice in small print a disclaimer with three important words: "results not typical." You'd think this would be a tip-off that losing a lot of weight through the company's program is unlikely. But no. To prospective dieters, it doesn't matter if the advertised results aren't typical. Why? Because most people think they're not typical. They're above average—and their results will be, too. Q: Are they? A: Nope. Most people drop out of the program after 10 or 11 weeks and lose only a fraction of the weight they had hoped to lose. Q: What can we do to make fewer errors? A: It helps to second-guess, to play devil's advocate with yourself. Years ago, Shell Oil taught its geologists how to do this, and their ability at picking oil wells that actually struck oil improved markedly. Q: What doesn't work? A: Many of the tendencies that predispose us to error are so ingrained as to be automatic. We cannot override them even if we wanted to. So simply imploring ourselves (or others) to "work harder" or "concentrate more" won't work. That's why money is so often ineffective at reducing errors. It's also why those baggage inspectors at the airport keep missing the fake bombs and guns that get sent through. What will work is designing products (or systems) in ways that block the errors that we know we are likely to make. Q: What's a good example? A: An electrical plug. If you look closely, one of the prongs on the plug is wider than the other; that way the plug can be stuck into the outlet only one way. And by doing that, you reduce your chances of being electrocuted. Which is a nice mistake to avoid. Q: Is this your first book? A: No, it's my second. My first book, Going Up the River: Travels in a Prison Nation, came out in hardback 2001 and in paperback in 2003. Q: Is there a third book on the way? A: There will be, but right now I'm still kicking around ideas.