A favorite interview question among hiring managers asks you to tell your serious mistakes and expose your weaknesses. “Tell me about a time you made a costly mistake?” or “What is your biggest weakness?” (Check out some variations: questions 14, 17 and 18 here). These questions provide a great opportunity to demonstrate your ability to mature from your experience, take responsibility, lead, work with honesty and integrity, and communicate well about uncomfortable subjects. But not all mistakes are created equal. Here is how to deal with the difficult “mistake” question.

In general, you need to think up a mistake you  made, express it concisely, and talk about what you did to correct the mistake and the overall lesson you learned. The best response then mentions a similar example showing that you did not make the same mistake twice. But what mistake should you choose to talk about? This is the more difficult part.

The mistakes we make

Suppose you plan a key event for your club—a dinner with a major speaker. You plan for fifty guests and only fifteen show up, with the resulting great embarrassment and waste of money. Now how you frame this mistake can vary, and the honesty of your interpretation can vary too. If the event has been well-attended for ten previous years, and there was little reason to think this year would be any different, then it is an excused mistake. Don’t use excused mistakes as your example, because they are too weak. No hirer cares to hear how something bad happened in something in which you were involved, but that, really, you weren’t to blame. Unfortunately, one tendency of interviewees is to try to rationalize all their “mistakes” into this category.

Suppose instead you failed to discover a competing event posted two weeks earlier. Here you are more culpable for the mistake. If you knew about the competing event, but other obligations made you too preoccupied to deal with it effectively, then again you have a mistake to explain. These are the kinds of mistakes to talk about. Hiring managers do not want to hear you rationalize all your mistakes, evade responsibility, or point out your pernicious flaws. They want to hear how an otherwise competent worker took responsibility for a genuine mistake and matured in the process. Sometimes the mistake can even be enormous, so long as you dealt with it in an impressive way. Tell them about those times, and hirers get a great glimpse into your prospects as a capable and productive worker in their organization. On the other hand, if you present an enormous mistake poorly or expose an incorrigible character flaw–this is too strong. You want to be Goldilocks and present the mistake that is just right.

A good mistake

One manager told me the answer he would give to a “mistake” question. He has a position in public relations where the communications he and his office issue must be clear, accurate, and exceptionally well-written. Every piece of writing may be scrutinized carefully by its recipient, and any error reflects poorly on his organization. (Hint: he’s in politics.) Early in his career, he drafted a letter for public release and handed it off to his superior, who pointed out a typo and told him to be more careful. One week later, he did it again—another typo. He was reprimanded. Another week went by, and he turned in yet another flawed document. This time, his boss had a serious talk with him: a boss’s time is too valuable to spend on proofreading his work for typos. But more importantly, there was a lack of sensitivity to the importance of his work, to the gravity and seriousness with which any error reflects on his organization if it gets into public view.

The realization that his work had this importance led to a refined sensibility. It was something he should have already known—an unexcused failure to understand his job—yet he needed to make this mistake several times before learning the lesson. But the goodwill of his boss gave him the chance to learn, and he has been extremely successful since then. This is a mistake worth talking about, and one hirers would admire you for discussing.

–James Jeffries