Hello! I am curios about how to know the "critical factors" in a market sizing practice, especially if I don't understand the product or market. For instance, once I did a case about "estimation of malaria patients in Africa". It turns out the the critical factor is whether people live close to swamp and whether people use nets or not. In another exercise, "number of organ donators in US", some critical factors include number of who volunteered to donate organs if they pass away accidentally. I feel that these factors are not so obvious and I need some specific background information to solve the problem.
I'm curious how could I know these information accurately, as there are so many ways to segment a market? How could I communicate with the interviewer so that he can give me a hint or background knowledge about the market sizing problem? Thanks in advance for your advice.