I don't ask this question a lot, but when I did, it was mostly as a nice starter to get started on a drill-down interview on that specific topic. The candidate

I don't ask this question a lot, but when I did, it was mostly as a nice starter to get started on a drill-down interview on that specific topic. The candidate is giving me the topic, and I would just dig into it and ask them to describe their approach and how it would change given certain constraints. Being able to lay out options in a mece-way (mutually exclusive and completely exhaustive) comes handy. I believe it's also a very difficult exercise if you didn't experienced the problem solving yourself.