How to use MECE on 'out of the box' cases?

Bain & Company BCG Case Interview Case Interview Framework McKinsey & Company
New answer on Aug 31, 2022
5 Answers
Anonymous A asked on Jan 18, 2022

Hey guys I was watching a video of an example case interview where they had an obscure problem that could not fit well into your traditional frameworks. They were asking for analysis for factors of market attractiveness and how to increase sales. 

To solve that case well, you needed to use your own MECE analysis rather than frameworks from victor cheng/case in point etc. I mean this makes sense and is expected, but I had difficulty finding good branches to break the problem down.

So how are you supposed to find choose good MECE branches for your analysis if the case does not fit with any framework and you have not seen the problem before? How do you decide what are good branches to segment the problem? It seems to me that it is very difficult to know a good tree structure if you have never seen the problem before - or am I missing something?


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updated an answer on Aug 28, 2022
McKinsey Senior EM & BCG Consultant | Interviewer at McK & BCG for 7 years | Coached 350+ candidates secure MBB offers


There are no “out of the box” cases, and this is certainly none!

 This question shows that you have not yet learned at all, how to properly build a problem solving toolkit. This is an extremely classical question arount idea generation (oftentimes called “Brainstorming” by consultants, but it has nothing to do with what people outside of consulting usually call Brainstorming!). 

You need to learn, how to build a robust logic for such questions. In essence: how to operationalize an aspect, then break this aspect down into its constituting elements, and then develop ideas against each sub-element on how to influence it into your desired direction. THIS is what you need to show in MBB interviews. And this is why books like Case in Point, Case Interview Secrets etc. are HORRIBLE and are RESPONSIBLE for thousands and thousands of candidates' failures!

My tip: get someone who REALLY understands consulting (and who did not just have a 1-3 years stint at it) to coach and mentor you on how to properly think through such problems. Then you will eat all these other candidates for breakfast, and an MBB offer won't be a problem at all. ^^

Cheers, Sidi


Dr. Sidi Koné 

(Former Senior Engagement Manager and Interviewer at McKinsey | Former Senior Consultant and Interviewer at BCG)


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replied on Jan 20, 2022
Bain | EY-Parthenon | Roland Berger | FIT | Market Sizing | Former Head Recruiter

Let me just highlight the following, to add to Sidi and Ian's answers:

“To solve that case well, you needed to use your own MECE analysis rather than frameworks from victor cheng/case in point etc. ”

Here's the thing: to solve well any case, that is exactly what you need to do. If you are just fitting the frameworks from victor cheng/case in point, then you are also NOT approaching correctly the other cases. 

It's a good thing that you've come across this case, because you actually need to re-think how you approach cases.

Strategy Consulting is NOT about using pre-made frameworks and as such Case Interviewing is NOT about how well you fit in some pre-made frameworks that you learned in a couple of books. 

Interviewers are not trying to hire people who do a good job memorizing Victor Cheng, but INDEPENDENT THINKERS. Independent thinker means that you can solve a problem on your own (break it down into parts, designing tests to understand the situation… or test hypothesis). Trying to force-fit the same “approach” that 80% of the other candidates are using… won't get you the job.

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Content Creator
replied on Jan 18, 2022
MBB | 100% personal interview success rate (8/8) and 95% candidate success rate | Personalized interview prep

Hi there,

This is literally the root of good casing and it's not something that can be answered just with a simple Q&A! Quite honestly, I work with my candidates across weeks and weeks to get this mindset across.

The short answer is you need to think about the problem on its own, independent of rigid frameworks you've seen before. Try to approach the problem like it's a real project and you are creating the project plan, or like it's an essay and you're figuring out your key paragraphs.

That's the short answer, but feel free to message me to truly learn how to do this!

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Content Creator
updated an answer on Jan 24, 2022
Unearth your spike & get the offer |ex-McKinsey | 120+ coachings & interviews @ McKinsey | ESADE MBA | Transition Expert

Great replies from the others on this topic. I will just add a little pro tip based on personal experience: try structuring anything in your daily life MECE as a little game for practice. 

For example:

  • How would you break down potential improvements in your apartment?
  • How would you decide on what to eat?
  • What movie should you watch tonight (none of course because you’re casing (-:)?
  • Or just simple categorization e.g what groups of people are there? What types of vehicles are there?

So many possible solutions for each one - try and explore them. Sounds silly but gets you away from those even sillier pre-made frameworks. 

To really get good at this you need to get a little “obsessed“ with structuring and practicing with the above is fun, easy, and ultimately powerful.

By the way, I did this not for preparation but actually started it at McKinsey. Really helps in the real world, too (as opposed to pre-made frameworks)…


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replied on Aug 31, 2022
50+ successful coachings / Ex-Mckinsey JEM & Interviewer / Industry + Engineering background

Dear A,

in general a good structure can be evaluated by a certain depth and breadth. The “depth” should be at least 3-4 levels while the “breadth” should cover the entire solution space. You can cross-check this with the MECE principles (For details see respective article on Preplounge), but the CE (collectively exhaustive) part is basically defining your breadth.

Finally, make sure to check for inter-linkages in your structure and point them out.


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Sidi gave the best answer


McKinsey Senior EM & BCG Consultant | Interviewer at McK & BCG for 7 years | Coached 350+ candidates secure MBB offers
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