McKinsey Interview- Non trad. Cases

Hello there,
Thanks for reaching out.
For public sector cases, I would say there are four key steps:
1. Formulate the problem: do not hesitate to clarify the problem and have the right level of informations (questions help).
2. Structure the problem MECEly: break down the problem into independent sub-problems (either demand/supply/enablers or problem1/problem2/problem3/global solution or else)
3. Ask questions: in this case, the best way to crack the problem is to ask the right questions and not take too many hypothesis especially if you don't know the sector.
4. Take the hint: maybe the most important advice. the interviewer will give you some hints about your issue tree and it will allow you to identify one of the root causes.
5. Sum up + identify creative solutions
For other rare cases (market sizing, out of the box cases like "how many crackers does Bill Gates eat every year (yes, true story)), my tip would be to be structured all the time but not to sound like a robot and bring "business accumen" in non-business related cases.
I hope that helps.
Please reach out to me if you have any questions,
Norah