Alternative and related questions:
What is the greatest challenge you have faced in your current job?
What has been your greatest achievement/accomplishment?
The meaning behind the question:
Great challenges can mean great achievements but they can also mean great failures! The interviewer hasn't necessarily suggested you pick a challenge that you successfully surmounted so a weaker candidate could easily be caught out here. Either way, it's a very useful question for an interviewer; they get to hear about an interesting success – or failure – on the candidate's part.
Your answer:
Without a doubt, the very best way to answer this question is to turn the question into the Top 10 question we covered all the way back in Chapter 2, "What has been your greatest achievement/accomplishment?"
Your greatest achievement or greatest accomplishment will undoubtedly have been a great challenge. If not then what is there to be proud about?
If you've already been asked that question separately then the best approach is to say you've already discussed that earlier and then move on to talk about another major challenge. As with many other interview questions, it's a good idea to have a second answer up your sleeve.
If at all possible, try to limit your answer to a challenge in your recent career history. Avoid going too far back. As a general rule when answering interview questions, if you are forced to cite an example of something which could be seen as a negative, then aim for something far back in your career history. Conversely, if you're given the opportunity to cite an example of something positive then aim to pick something recent.
Example:
The greatest challenge I've faced in my career to date has to be the key role I played in helping my company survive the recent recession. The company was undoubtedly ill-prepared for the advent and impact of the recession; their financial reserves were just too weak. After a spate of redundancies, those of us who were left faced an uphill struggle to keep sales levels up and costs down while maintaining our standards of customer service. I learned a great deal from the experience. It was a great challenge. While we certainly did have a tough time of it, we successfully rode out the recession and the cost control measures which I personally devised and implemented ultimately resulted in a significantly healthier bottom line than we had had before the recession.