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How to have a comprehensive structure for interviewer led case interview

interviewer led McKinsey Structure
New answer on Aug 30, 2022
4 Answers
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Anonymous A asked on Oct 26, 2018

In the case interview with interviewer led format, the opening question will usually be "what factors to consider". How do I get a comprehensive answer (structure) in the short time?

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updated an answer on Oct 26, 2018
Bain & Co interviewer (~3 years) | MBB-prep focused | Expert: Market Sizing; P&L cases | 50+ coachees at MBB


Great question, and good point from Gwennael!

I would add that even if you are not leading the interview, you will still be judged on your ability to drive an independant piece of work. You might be cut in your reasonning and brought to a completely different aspect, and this is fine (it can be positive and negative, don't jump to conclusions)

What you need to focus on, is how to structure the smaller pieces of a big problem. When you hear questions as:

  • What are the revenues drivers?
  • What are the main costs?
  • What could be the risks of doing this?

A red alarm should ring in your head: you need to structure.
For instance for the second question, NEVERstart a list of costs such as "Oh we can think about labour costs. Hum, also, hummm, raw materials, maybe. Silence. Also, distribution costs and hummm".
Instead, ask for 5-10 sec to think about the main costs and come with a structured answer: "I have identified three main costs: two variable costs and a fixed cost. The two variable costs are X and Y and the fixed cost is Z. Have I covered the most important costs or should I investigate further?"

The content is similar but you will definitely tick the box "structured" on a interviewer led case. You will notice that I structured the costs further, and this is generally appreciated. Often, when you have a possibility to create buckets, do it!
Another example is for risks, that can be structured into for instance: financial risks (for example currency), reputational risks (for example brand), "people" risk (for example union-related risks) etc.

I hope it helps!


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replied on Oct 27, 2018
McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School


It's exactly the same as with the candidate-led case. It's not important who leads the case if you can solve cases.

The structure really depends on the case. Here is some inspiration for you. Below you can find a list of the most common case types and some high-level recommendations on structuring:

  1. Market sizing - structuring from the supply or demand side. Structuring using a formula or using an issue tree
  2. Profitability - basic profitability framework. Remember about different revenue streams and product mix
  3. Market context cases (Market Entry, New product, Acquisition, etc). Always start with the big picture "Market". Finish with something specific question related to the case (e.g. How to enter?"). For the buckets in the middle - choose the most important ones for this particular case (Competitors / Company / Customers / Product)
  4. Operational math problem (e.g. Should we increase the speed of an elevator or just buy a second one? How should we reduce the queues? Etc.) - Structuring as a process / value chain, with inflows, operations, and outflows
  5. Cost cutting - I provided the recommendations on structuring it here:
  6. Valuation - Purely financial structure with cash flows, growth rate, WACC / hurdle rate, etc.
  7. Synergies - revenue synergies (price, qty, mix) and cost synergies (value chain).
  8. Social / economics cases (e.g. How to improve the quality of life in the city? How to increase the revenues of the museum?) - huge variability. Practice 3-5 social cases before the interview.

So I recommend you to use a flexible approach depending on the type of the case. It definitely comes with practice. Here is an algorithm on how to develop this skill:

  1. Make sure you understand all the different types of cases that you may face
  2. Identify the most appropriate structure for each type
  3. Solve 30-50 cases and try to understand where do they fit in your categorizations
  4. Based on your experience think of the potential variations in structures within each of the case types

Best of luck!

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Content Creator
replied on Aug 30, 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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replied on Oct 26, 2018
Ex-MBB, Experienced Hire; I will teach you not only the how, but also the why of case interviews

You still need to prepare a framework just like you would in an interviewee-led case; only (major) difference will be the interviewer guides you and saves time by telling you what area of said framework you should dive into

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Ben gave the best answer


Bain & Co interviewer (~3 years) | MBB-prep focused | Expert: Market Sizing; P&L cases | 50+ coachees at MBB
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