It’s one of the most dreaded questions in any job interview. The Denver Post wanted to know the best answer, and I told them exactly what I’m looking for when I ask it: Problem solving capabilities, taking responsibility, and how potential employees will do better the next time. My top suggestion is to be honest, but plan ahead. Choose an example that’s reasonable, but maybe not the biggest blunder you’ve ever made!
Your interviewer isn’t actually looking for the biggest mistake possible. They want to see if and how you own up to mistakes, because we all make them. They want transparency and to gauge how well you communicate. They’re looking to see how you fixed the problem, and steps you’ve taken to ensure it doesn’t happen again. The reality is that it doesn’t really matter what the mistake was (to some degree!). What matters is that you own up to it and manage it well.
Before any interview, have a few examples tucked away. As a bonus, it makes you more human and might give you and the interviewer something to bond over.