Chance of receiving a market sizing case

Market sizing
New answer on Dec 31, 2021
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Anonymous A asked on Oct 25, 2018

Hello, I assume that my upcoming interview with BCG will be 30 - 40 minutes, likely the shorter end. Is a market sizing case likely?

I'm trying to understand the best way to prepare and which cases to allocate my time to.

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replied on Oct 25, 2018
Ex-MBB, Experienced Hire; I will teach you not only the how, but also the why of case interviews

At MBB, very unlikely you'd have more than a high level, top down, back of the envelope market sizing exercise; even that is fairly uncommon in my experience.

What's the optimum way to prepare? Get a coach. Short of that... focus on the case mechanics, which are portable skills you can reuse no matter what case you are being given. I'd focus on understanding a specific type of case only much later in your prep, if ever - you have to be ready for the unexpected. If you know how to think, you'll be fine.

PS: Expect to spend over 100 hours on your prep; case interviewing isn't hard, but you need to make it second nature so you are able to really focus on cracking the case during the interview, vs. struggling to remember what you are supposed to do when.

Good luck.

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replied on Oct 26, 2018
McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School


BCG gives both market-sizing cases as a part of the bigger case and standalone market sizing cases.

Chances of getting one during one of the interviews are high, thus solving MS cases is an absolute must-have skill.

I usually give a homework of 10 MS cases that cover almost all possible topics and tools and go through all of these cases during one session. Feel free to reach me.


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Content Creator
replied on Dec 31, 2021
MBB | 100% personal interview success rate (8/8) and 95% candidate success rate | Personalized interview prep

Hi there,

Providing some market sizing thinking for anyone revisiting this Q&A:

Remember that there's rarely a "best" answer with market sizing. What's important is that you break down the problem the way it makes sense to you. Importantly, break it down so that the assumptions you make are the ones you're most comfortable in.

For example, do you know all the major brands? Great go with that. Do you understand all the segments of that country's population (either age or wealth or job breakdown)? Go with that. Do you know the total market size of the tourism (or hotel) industry? Then break it down that way.

Some tips:

  1. Just like in a case, make sure you understand the question - what are you really being asked to calculate
  2. Decide whether a top-down or bottom-up approach is best
  3. Figure out what you know you know, and what you know you don't know, but could estimate
    1. This helps you determine how to split out buckets
  4. Stay flexible - you can start with a "high-level" market sizing, but gauge your interviewers reaction....if it looks like they want you to do more...then go along level deeper in terms of your splits
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Guennael gave the best answer


Ex-MBB, Experienced Hire; I will teach you not only the how, but also the why of case interviews
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