Prepping for First Round in Two Weeks

Case Interview First Round firsttime
New answer on Aug 14, 2020
4 Answers
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Anonymous A asked on Aug 06, 2019

Hi everyone, first time posting here. A little bit about my background: I'm a recent J.D. graduate with interest in consulting - went to law school straight from college but solid math skills. I just received my first round interview request from one of the MBB. My consultant friend has suggested me to do as many case interviews and watch all the Victor Cheng (think that's his name?) materials as I can.

What are your thoughts to prep for this interview - what would be an ideal attack plan? All online wisdom suggests that one should do at least 50 case interviews before his first round (I have not done any), but I only have one friend who's in this industry, and all commercial coaching seem pretty darn expensive.

Any insight would be much appreciated! : )

Many thanks,

A clueless applicant

P.S. I just finished bar exam and haven't started working so I am free everyday to prep for this interview.


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replied on Aug 06, 2019
McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School


First of all, try to reschedule the interview. There is absolutely no penalty for it unless it's an on-campus recruiting.

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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replied on Aug 06, 2019
#1 Coach for Sessions (4.000+) | 1.500+ 5-Star Reviews | Proven Success (➡ | Ex BCG | 10Y+ Coaching

Hi Anonymous,

in terms of the interview preparation I would recommend the following:

  1. Define a calendar for your preparation. Identify how many hours you have before your expected interviews, then allocate a time slot for preparation in your calendar for each day, working on the following points.
  2. Read Case In Point or Case Interview Secrets for a general understanding of what a consulting interview is. Don’t focus on the structures proposed in the books though, as they are not good enough nowadays.
  3. Start reading good MBA Consulting Handbooks – you can find several for free online (Insead is a good one to start). Read the cases and try to apply your structure. Whenever you see there is something missing, upgrade your structure with the new insides. Try to read at least a new case per day – in this way you will absorb a lot better the information with constant learning. Structure your remaining daily preparation with at least 5-10 minutes per day for each of the following: market sizing, fit questions and mental math.
  4. After you have read the first 10 cases in books/handbooks and basic theory, start to practice live. There is a relevant part of the interview score that is based on your communication, which you cannot practice at all if you read cases only. Keep track of your mistakes and see if you repeat them. If so, try to identify the source of the mistake (feedback of experienced partners would be particularly useful for this). Be sure to focus on both fit and case.
  5. Once you feel you are not improving anymore, if you have a tight time constraint or if you want a realistic assessment of your level, consider using support from experts to strengthen your performance
  6. Before the interview, be sure to prepare your questions for the interviewer – great way to show you prepare in advance and to connect more with the interviewer for a good final impression.

If you feel you don’t have enough time (many people spend 100-150 hours to properly prepare before MBB interviews) you may consider rescheduling the first round, usually consulting companies are quite accommodating unless it is a last-minute request.



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Anonymous replied on Aug 14, 2020

Hey, here are some tips for your first interview!

1) Practice mental calculation daily (percentages, decimal places, large numbers, arithmetic)

2) Cases, cases, cases – do as many as you can. Try to find a person who is now working or has worked in the past at the MBB's recruiting and ask them to simulate an interview with you. Or book a coaching session here on Preplounge.

3) Prepare and practice personal fit interviews – they are as important as the cases. Write down your stories, practice telling them with your fellow students, or with an expert (again, here on Preplounge)

4) Be aware of your mental state – try not to stress too much before and during the interview

5) If you get rejected, it's not the end of the world, do prepare yourself mentally for this thought!



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Anonymous replied on Aug 06, 2019

First of all - huge congratulations on getting an interview with one of the MBB firms. Considering you were able to achieve that and are now actively looking for help, I'd say you are anything but "a clueless applicant" :)

My most important piece of advice, based on my experience successfully transitioning from tech to banking to consulting (at McKinsey! and interviewing and preparing 200+ candidates: it's better to delay your interview to ensure you are prepared than to just go ahead and cross our fingers. MBB firms are usually pretty flexible about this so if you feel you need more time, ask that your interview is extended (message me directly if you want to discuss how to do this successfully).

Onto our question: here are my top preparation tips:

  1. Practice A LOT with REAL PEOPLE, both for the case and interpersonal interviews. Practising by yourself is just not enough! Yes, it can be expensive to practice with expert coaches like myself so I suggest:
    1. practising with other applicants, like yourself. Set up 2 hours to do a case for each other. The beautify of this is you learn both by practising solving the case. And by watching someone else solve the case and giving them feedback.
    2. asking consultants and ex-consultants you know who wouldn't mind helping you practice
    3. Invest in a few sessions with an expert coach who has previously interviewed for an MBB firm and can give you very clear, pointed, feedback. The advantage of doing at least a few sessions is they can then see your improvement and help you refine further before your interview.
  2. Use PrepLounge resources - need I say more? It's great!!!
  3. Use Victor Cheng's resources - I found VC particularly useful to understand the wonderful world of consulting and in particular good habits, as well as bad habits for problem-solving: Case in Point is a very helpful resource to pinpoint key principles and his daily newsletters provide handy insights in a digestible way. Also, listen to LOMS, if you can afford it.
  4. Problem Solve real businesses situations (e.g. those you see in the FT, at work, and throughout your day-to-day) - The more you make consulting a part of your every day, the more natural it will become. I remember it actually helping with my job at the time in terms of solving problems and presenting solutions to my boss. Or if you hear something on the news, think about how you would solve the problem yourself - how would you structure it, what would you analyse, what's your hypothesis, etc.
  5. Spend time on websites of consulting firms - this is both to get a feel for the firms and to learn about the interview process. e.g. McKinsey's website has loads of tips for what they expect - a lot of people skip this and it shows!
  6. Practice your Maths (no calculators!) - from everyday things like figuring out discounts at the supermarket and calculating percentages when watching the news to more structured things like using Victor Cheng's maths practice online
  7. Have fun and ask questions! It can be quite tiring - think of it as learning to exercise a new set of muscles in your brain. But it should be fun so enjoy it! :)

Shoot me a message if I can help with anything! I offer discounts as well so happy to discuss those if you're really having trouble with the cost of an expert.



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Vlad gave the best answer


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