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What to do during a Case Interview

Anonymous A

Hey guys,

I will soon have my first Case Interview for a job. I practised approx. 50 cases alone. So, I wondered what it's like to to a case with the interviewer in real life. The interviewer reads the case and I take a minute to structure my thoughts and tell hime how I will approach and structure the problem? Can I take notes on my points and explain my thinking after that or should that be simultaniously? Can I do my calculations in detailed writing and should I explain every move (e.g. when calculating 910*840 - 128*240)? What do do (seriously) when I am stuck, how to ask for advice in that case?

I just can't imagine.. I watched many solution-videos on preplounge but I can't think of what to do in real life.. do I bring my own pen and pat (:D)?

Feeling so stupid right now.. but thank you in advince! Im grateful for every answer:)

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Vlad replied on 06/06/2018
McKinsey / Accenture / Got all BIG3 offers / More than 300 real MBB cases / Harvard Business School

Hi,

First of all - you should definitely practice cases with someone - just reading the cases is not enough.

It's absolutely vital to have a structure, business sense, and the right fit. But if you can't communicate it properly, it is a signal that you will not be able to communicate your ideas to the client as well.

Here is the approach to the proper communication during the case:

1) Start with clarifying questions:

https://www.preplounge.com/en/consulting-forum/clarifying-questions-1786#a3956

2) Communicating while structuring. Here is a long post by me on how to communicate the structure during the case study:

https://www.preplounge.com/en/consulting-forum/how-to-communicate-its-structure-for-the-case-study-1313#a2806

3) Using hypothesis. I made a post about hypothesis here:

https://www.preplounge.com/en/consulting-forum/how-to-state-a-hypothesis-and-match-to-the-structure-1156#a2268

4) Communicating while making calculations:

  • Always tell the interviewer your approach
  • Check with the interviewer that your approach is correct
  • Come to the interviewer with some preliminary answers
  • Check your assumptions with the interviewer

5) Communicating during the analysis of graphs / tables

  • Take a minute to look at the graph. Read the graph title. Look at the graph type and define the type (pie chart, line chart, etc). Look at the legend (ask for clarifying questions if necessary). Identify whats going on on the graph. Look for: Trends, % structures. Look for unusual things - correlations, outliers,
  • Make 3-4 conclusions from the graph. Think out loud on potential hypothesis on what could be the root cause / what are the consequences
  • Prioritize the most important for your current analysis and move forward with the case

6) Communicating while having questions on creativity

  • Ask an interview for a minute to think
  • Think of several buckets of ideas (e.g. organic growth / non-organic growth / differentiation). Remember to think as big as possible
  • Narrow down to each bucket and generate as many ideas as possible
  • Present the structure (buckets) and then your ideas

7) Communicating your conclusion. You can find a good example I've posted here:

https://www.preplounge.com/en/consulting-forum/how-much-answer-first-should-the-conclusion-be-1231#a2493

8) Communicating your FIT stories

Use the top-down approach while communicating your stories. "The Pyramid Principle" is the must-read by ex McKinsey on this topic.

I recommend using the STAR framework:

  • In Situation, you should briefly provide the context, usually in 1 or 2 sentences
  • Task usually includes 2 or 3 sentences describing the problem and your objective.
  • Then you provide a list of specific actions you took to achieve the goal. It should take 1 or 2 sentences per action (Usually 3-4 actions). Note that the interviewer can stop you any minute and ask for more details.
  • The results part should have 1 or 2 sentences describing the outcomes. This part is finalizing your story - make sure it can impress the interviewer and stay in the memory.

Best!

Francesco replied on 06/07/2018
Ex BCG | MBB Specialist | #1 Expert for coaching sessions (1400+) and recommendation rate (100%)

Hi Anonymous,

I have replied below to your questions. As mentioned by Vlad, you should definitely do some live practice before the interview, that can help you a lot in improving, in particular for what concerns your communication.

The interviewer reads the case and I take a minute to structure my thoughts and tell hime how I will approach and structure the problem?

The process I would recommend is the following:

  • The interviewer reads the prompt
  • You repeat the information
  • You clarify the goal, business model and potential constraints we have
  • You ask for one minute of time to structure
  • You can then present your structure

Can I take notes on my points and explain my thinking after that or should that be simultaniously?

Assuming you refer to questions asked by the interviewer, both at the beginning and during the case, you can always ask for 1 minute (beginning of the case) or 30 seconds (during the case) to structure your approach and develop it on paper. After that, you can present your points.

Can I do my calculations in detailed writing and should I explain every move (e.g. when calculating 910*840 - 128*240)?

You should present the formula without numbers, align with the interviewer on the formula and once confirmed it’s ok, proceed with the math. You don’t need to go though all the numbers of the math so far that you aligned on the formula before, just present the main intermediary results to align during the process.

What do do (seriously) when I am stuck, how to ask for advice in that case?

If you get stuck you should:

  • Repeat all the relevant information you received until the moment
  • Ask for one minute of time to think
  • If still stuck, ask for help

Do I bring my own pen and pat?

I would suggest bringing them as backup, but you can normally use the ones the consultant will offer you.

Best,
Francesco

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