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Any good way to improve how to be structured for brainstoming questions and conclusion?

Case Case Interview Structure
Recent activity on Mar 11, 2018
4 Answers
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Anonymous A asked on Mar 10, 2018

Hi all, thank you very much for your inputs. I've got rejected at second/final round of some firms. I think my initial structure is quite good, i have a good business sense and good fit also. But I think I always fail at being structured during brainstorming question, i have many ideas coming at the same time and i don't take enough time to calm down and announce it in a structured way, same for the conclusion, i announce it in a chronological way but seems not structured enough.

Do you have any exercices/books/tips i could practice to be more structured for brainstorming question and conclusion? Maybe to be more structured in general? (It is not a framework issue, initial structure is quite good).

Thank you


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updated an answer on Mar 11, 2018
#1 Coach for Sessions (4.500+) | 1.500+ 5-Star Reviews | Proven Success (➡ | Ex BCG | 10Y+ Coaching

Hi Anonymous,

for what concerns the structure for brainstorming, I would suggest the following:

  1. Recap the situation until that moment
  2. Ask for one minute of time to structure your thoughts
  3. Identify some key MECE areas. Potential division includes: Number of units - Price per unit (eg to identify the components to reduce costs); Current-New (eg to structure product, customers, distribution channels); Financial-Non financial (eg to compare ways to enter a market)
  4. Brainstorm inside each of the areas. Your creativity in this area is directly correlated with the number of cases you have done

I provided an example below:


Interviewer: So, generally speaking, how would you decrease the cost of raw materials?

Step 1: Recap the situation

Interviewee: So, if I understood correctly, you would like now to move to the elements that could decrease this cost. If it is fine for you, I would like to do a small recap and then move through the key elements that can help to do so. At the beginning you asked me what brought a decline in profits. We have identified the problem lays in Product A, and in particular in the cost area. We then found out that the main increase in cost was related to raw material.

Interviewer: That’s right.

(Notice you may have gained 30 seconds of additional time summing up information)

Step 2: Ask for one minute of time to structure your thoughts

Interviewee: Do you mind if I take 1 minute to think about it?

Interviewer: Please take your time.

Step 3: Identify some key MECE areas

Interviewee: Thanks; I believe there are two key areas to decrease the cost of raw material; we may decrease the cost of each unit, or we may decrease the number of units we buy. I would like now to go a bit deeper in these two components.

(Notice that even if you are brainstorming, you are first presenting a list of the MECE areas. This is fundamental to brainstorm correctly)

Step 4: Brainstorm inside each of the areas

Interviewee: Well, in order to decrease the cost per unit we may do a couple of things, keeping in mind we want to maintain revenues at the same level:

  1. we may use lower quality material;
  2. we may negotiate with the supplier;
  3. we may look for someone else as supplier.

In order to decrease the number of units, we may do two things:

  1. we may start to use a more efficient technology for our raw material, so that we have to buy fewer units;
  2. we may also substitute some of the units with other type of materials, ideally cheaper.


For what concerns the conclusion I would recommend the following:

  1. Repeat the question. As an example: "Our goal was to understand (i) why profits are declining and (ii) how we could increase profits"
  2. Answer first solution. As an example: "After our initial analysis, we found out that:
    1. As for your first question, profits are declining due a decrease in profits in division 1. More specifically…[SPECIFIC FINDINGS]
    2. As for your second question, in order to increase profits. We would recommend shutting down division 1. That’s for the following reasons…[SPECIFIC FINDINGS]"
  3. Provide next steps. As an example: "As additional elements to explore, we would like also to consider the following elements…[RISKS/NEXT STEPS]"

It also seems you may improve your communication. The best way to properly communicate the structure in a brainstorming question would be the following:

  • STEP 1: mention first the macro areas of your framework. “In order to help our client, I would like to focus on three main areas. Number 1 we may work on [FIRST TOPIC], Number 2 on [SECOND TOPIC], Number 3 on [THIRD TOPIC]. If this is fine for you, let me go deeper in each of them”
  • STEP 2: provide details for each macro point. “In area Number 1, this is what I would analyse. First, I would like to cover [FIRST STEP OF FIRST TOPIC]; second, I would like to focus on [SECOND STEP OF FIRST TOPIC]; next, I would like to work on [THIRD STEP OF FIRST TOPIC]. In area Number 2, this is what I would analyse. First,(…)”

The fastest way to improve on structuring AND communication is to find great partners or experts specialized on that, as this allows you to improve on both the content of your structure and the way you present it.




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replied on Mar 10, 2018

Hey anonymous,

There's two different ways of approaching this problem, depending on whether you are doing candidate or interviewer-driven cases.

Let me start by with the best tips that applies to both cases (this should be your major aim!)

  • for creativity questions during the case: think about what are the different ways of breaking down the problem (e.g., value chain, 4Cs, customer journey), so that it's now much easier to brainstorm in a structured way - your first level is immediate and you just need to brainstorm some ideas for your second level [Note: this is one of the most used methods in real life consulting projects, so it's really impactful and interesting for you to present to the interviewer)
  • for recommendation, you just need to follow the golden rule approach described below (again it's so powerful because it's what we do in real life!): I'm still puzzle with the number of candidates that confuse a recommendation with a synthesis
    • what's your recommendation;
    • supporting arguments;
    • risks associated with your recommendation;
    • next steps/analysis

Finally, a small trick if you doing interviewer-led cases, e.g., McK, where the interviewer really cares about the end product rather than the brainstorm process: you can brainstorm in a disorganized way, and they when you have your ideas, you just need to group them in some logic way. This is what a typicall McK new hire do in their first days on the job, before mastering the process!



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replied on Mar 10, 2018
McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School


Several tips here:

1) Always ask an interview for a minute to think

2) Think of several buckets of ideas (e.g. organic growth / non-organic growth / differentiation). Remember to think as big as possible

3) Narrow down to each bucket and generate as many ideas as possible within each bucket

4) Present the structure (buckets) and then your ideas

Creativity is in direct correlation with your business judgment. Business judgement is directly related to industry knowledge. Focus on the most common industries in the following priority (sorted by probability of getting a case): 1-retail and CPG; 2-airlines; 3-Telecom; 4-banking; 5-natural resources; 6-tech

There are several sources of infotmation to develop industry knowledge:

1) Cases - you simply solve 50-70 cases and get a broad knowledge of different industries, common pitfalls and questions. The key here - find good partners who already had case interviews with MBB companies

2) Company reports, equity reports, IB roadshow docs - usually have a good overview of company and industries. Annual company reports are probably the bast source of information about the industry

3) HBS cases - quite useful, but not sure if lot's of them available publically. Probably worth buying

4) Books - one good book about airlines with numbers and industry analysis can give you all needed industry knowledge

5) News, Industry blogs

For each industry, you should understand:

  • Revenue streams
  • Cost structure
  • Margins
  • Key performance indicators
  • Key revenue drivers
  • Industry trends

Also some comments about particular industries:

1) Retail - make sure you understand key retail metrics (P&L lines, same store sales, revenue per square meter and per person, etc) and how distribution works as well as its metrics (share on shelf, etc)

2) Airlines - read about profitability issues, different routing models, cost structure, industry metric s like load factor and make sure you know all possible additional revenue streams

3) Telecom - I would read industry reports and try to understanf how telecom is transforming with internet penetration and tech innovations

4) Banking - you should know the key products in corporate and retail banking and how they earn money (Interest, commision, transactional)

5) PE / M&A - go through available case examples and read about different PE strategies

Good luck!

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replied on Mar 10, 2018
Former BCG interviewer
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Francesco gave the best answer


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#1 Coach for Sessions (4.500+) | 1.500+ 5-Star Reviews | Proven Success (➡ | Ex BCG | 10Y+ Coaching
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