How do successfully complete my case interview?

Case Interview Deloitte Monitor
Recent activity on Feb 03, 2019
2 Answers
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Priyesh asked on Feb 03, 2019

Hi All

I have succesfully chosen for a case interview with one of the big 4 consulting companies in South Africa

The initial interview was with the director and went well as she saw something in me that she wanted to horne further

I was selected for a case interview in less than 4 days away and am not sure if i will have enough prep time.

I want to make a great impression and have been consulting with lectures (im a MBA student and recently completed my PG Dip in Management last year as well), colleagues in consulting and a wide variety of online case studies and websites.

I have completed 2 case studies thus far and have not faired as well as i have hoped, with time running out i need a fast but effective study plan

Can anyone help

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Content Creator
replied on Feb 03, 2019
McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School


Please reschedule the interview. There is absolutely no penalty for rescheduling. You can even tell them openly that you need some more time to prepare. 2 cases is definitely not enough.

Here are some guidelines that I usually post for prep questions:


I recommend the following approach:

1) Start with "Case in point" book - you can download this book for free everywhere. It's not the best guide on how you should approach the cases, however, it will give you the basic understanding.

2) Start practicing cases with partners here or find them locally. !!! Find experienced partners or coaches who can provide a good feedback!!!

3) Purchase and read Viktor Cheng Book (Amazon Kindle store) and listen to LOMS(his website). I recommend to reread the book and listen to LOMS every 15 cases. Every time, having more experience, you’ll be finding something new.

4) Practice fast math

  • Learn how to multiply double digit numbers (
  • Learn the division table up to 1/11 (i.e. 5/6 = 83.3)
  • Learn how to work with zeros (Hint: 4000000 = 4*10ˆ6)
  • Use math tools (Mimir math for iOS), Math tool on Viktor Cheng website to practice

5) Below you can find a list of the most common case types and some high-level recommendations on structuring:

  • Market sizing - structuring from the supply or demand side. Structuring using a formula or using an issue tree
  • Profitability - basic profitability framework. Remember about different revenue streams and product mix
  • Market context cases (Market Entry, New product, Acquisition, etc). Always start with the big picture "market". Finish with something specific to the case (e.g. How to enter?"). Structure it as if you are defining the work streams for the real project.
  • 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
  • Cost cutting - I provided the recommendations on structuring it here:
  • Valuation - Purely financial structure with cash flows, growth rate, WACC / hurdle rate, etc.
  • Synergies - revenue synergies (price, qty, mix) and cost synergies (value chain).
  • 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

6) Also, I would try to 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

7) ! Important: don't forget about the FIT interview part. Crafting you stories and backups stories will require a couple of weeks!


Here is a good list of articles regarding the different parts of the case:

1) Start with clarifying questions:

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

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

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:

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.


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Priyesh on Feb 04, 2019

Unfortunately im unable to reschedule the interview. Im going to try and work through all the information and atleast 10-20 cases by the time of the interview. I have chatted to a few of the current consultants and they have advised as long as i can structure my answers correctly i should be ok with the case interview.

Vlad on Apr 17, 2019

That's selection bias

replied on Feb 03, 2019
Ex-MBB, Experienced Hire; I will teach you not only the how, but also the why of case interviews

Ideally, you'd have a lot more time. With the interviews coming up so fast now, postponing doesn't look like it would happen (I'd still encourage you to call in on Monday morning and ask fora reschedule, but your odds aren't good less than a week before the interview)

At this point, your best bet is to do some intensive prep with someone who knows what he/she is doing. i.e., with a coach.

Short of working with a coach, I suggest the following:

1. Review the case mechanics

2. Listen in to Victor Cheng's 6 hours of free video on YouTube. Well worth your time; I advice all my clients to do this

3. Review all the feedback you've been given on the case practices you did in the past. If you don't understand some feedback, reach out to the person who gave it and ask for clarifications

4. Don't forget to prep the fit as well

5. During the interview, don't forget to listen. A natural tendency is to show off a little bit and try to speak too early. Take it easy, be humble

6. Remember this isn't the end of the road anyway, there will be other opportunities with this and other companies. Relax

7. Rest. You want to be fresh for the interview, so no/little alcohol before and plenty of sleep if you can

Good luck.

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Priyesh on Feb 03, 2019

Thank you. Will do so

Vlad gave the best answer


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McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School
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