How do you handle and prepare for a case that doesn't fit well into a pre-defined framework?
First off, it's rare to get one of these weird cases that doesn't fit a framework. That being said, it happens from time to time. My estimate is it happens less than 2% of the cases.
For example, out of my 63 cases as an interviewee, I didn't get a single one that was totally off the wall.
Keep in mind that the interviewer has to have data for your to analyze... and it's much harder to come up with a fake data set for some weird case than it is to just use a real client situation (disguised to protect confidentiality).
So the likelihood of getting a weird case interview is probably proportional to the likelihood of the interviewer having worked on a bizarre client situation.
The ones that end up being a little unusual are case interviews based off of pro-bono work for non-profits or government agencies... where the goal is not necessarily to make a profit.
* The Mayor of San Francisco is a new pro bono client and they have asked you how they should solve the homeless problem in San Francisco? Specifically, how does the city reduce the number of homeless people.
Here are some more I just made up (you wouldn't get any of these in a case interview, but the type of thinking involved is similar to that used in a weird case):
* Your friend has gotten a bunch of job offers and is deciding between going X profession or Y profession. She has asked you to help her decide. What do you do?
* You go to turn on your DVD player and nothing happens. What do you do? And in what order do you do it? And why?