Hi there,
You take a few things for granted here, so let's back up.
If your goal is to solve the case, and the structure is your analytical blueprint for doing so over the next 40 minutes, then every element in your structure must be tied to the overall objective. Moreover, it must be a prioritized list of things to analyze, neglecting those things with relatively minor impact.
- The question is: how do you know whether an analytical stream in your structure has impact and helps you solve the case?
- The answer is: you don't know but you establish it by hypothesizing and you do so for each element in your structure i.e., give your explanation as to why this element is there and what you think may be the outcome if we were to analyze it.
Leading with a hypothesis is merely prioritizing from this list according to the highest impact per time spent. Here, too, you should argue as to why you want to start with x and not y, before proceeding to analyse x.
Note: the above only applies to candidate-led cases and is really quite different from interviewer-led (McKinsey) cases.
Hope this helps. Best of luck!
Moritz