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What is the best way to start prepping for case interviews ?

Anonymous A

I am a rising senior looking to get into consulting but I have no background in it. I was wondering what the best place to start is ?

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Dorothea
Expert
replied on 07/07/2018
Ex-Oliver Wyman with 100% interview success rate - specialized in female career coaching

Hi,

I suggest you follow the steps below:

  1. Get an idea about theoretical concepts: As you do not have any experience in consulting or at least the preparation of consulting interviews, I suggest you start with working you the theoretical concepts with which to solve case studies. There are several books on the market, like „Case in Point“ or „Case Interview Secrets“, or you may use the „Bootcamp“ here on Preplounge. This will teach you how approach different types of case studies in general and guide you through the basic concepts.
  2. Start improving your calculation skills and general knowledge about different industries: Start practicing both mental arithmetic and how to do calculations without a calculator - this will become very important as almost every case involves a certain amount of calculations. Further, if not already doing so, start reading newspapers and get an idea of different industries (what is this, how do they work etc.) - this will help you to get a better understanding of the context of different case studies.
  3. Solve case studies with other people: This is an essential part of the preparation process. Practice solving case studies until you feel it is now routine. The key here is to not only do this on your own but most of the time with other candidates. This will (1) put you in a „real“ interview situation when you take the role as interviewee and (2) make you aware of frequent mistakes people make whenever you are in the role as interviewer. There is no right number of cases you should solve before doing real interviews.

Hope this helps!
Dorothea

Vlad replied on 07/08/2018
McKinsey / Accenture / Got all BIG3 offers / More than 300 real MBB cases / Harvard Business School

Hi,

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 (https://www.youtube.com/watch?v=6ndkkPZYJHo)
  • 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: https://www.preplounge.com/en/consulting-forum/operations-cases-mck-1105#a2134
  • 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) After solving 15-20 cases start preparation for the tests (Serch for PST / BCG online test here on preplounge)

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

PS

Here is a good list of articles regarding the different parts of 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 07/09/2018
Ex BCG | MBB Specialist | #1 Expert for coaching sessions (1400+) and recommendation rate (100%)

Hi Anonymous,

I would consider the following steps to prepare:

  1. Read Case In Point or Case Interview Secrets for a general understanding of what a consulting interview is. Don’t focus too much on the structures proposed in the books though, as they are not good enough nowadays
  2. Start to read MBA Consulting Handbook – 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
  3. After having 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 particular useful for this)
  4. 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 experts’ support to strengthen your performance

Best,

Francesco