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Estimate of time needed for preparation

time for preparation
New answer on Aug 31, 2020
6 Answers
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Anonymous A asked on Jun 16, 2019

Hi there! I am starting preparing for the case interview and I am currently considering around 8-10 weeks of preparation. Of course this depends heavily on how fit one is and also on the time that she/he can invest, but what would be your estimate?

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Content Creator
replied on Jun 17, 2019
#1 BCG coach | MBB | Tier 2 | Digital, Tech, Platinion | 100% personal success rate (8/8) | 95% candidate success rate


Of course, it depends person to person. But I have a few "baseline" suggestionss:

  • Aim for a few hours a day
  • Start "heavy" on fast math, and background knowledge/reading (building industry knowledge, reading case books, reading The Economist/FT/BCG insights)
  • Always go steady with actual casing (aim for a minimum 25 cases by the time you're done)
  • Work on fit/behavioural questions just 2-3 weeks before
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replied on Jun 16, 2019
McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School


8-10 weeks with 4-5 hours per day should be enough. It also depends on how efficient you are in the process. 2 ways to make the process efficient:

  1. Find experienced case partners
  2. Work with an experienced coach

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).

4) Start with the following cases and apply some high-level recommendations on structuring:

  1. Market sizing - structuring from the supply or demand side. Structuring using a formula or using an issue tree
  2. Profitability - basic profitability framework. Remember about different revenue streams and product mix
  3. 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.
  4. 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 outflow

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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Content Creator
replied on Aug 31, 2020
McKinsey | NASA | top 10 FT MBA professor for consulting interviews | 6+ years of coaching

there are 4 aspects of the application process you have to focus on:

  • CV and cover letter: prepare impactful documents that highlight your achievements, skills, and motivation.
  • Test: you should understand if your office assesses candidates with PST, SHL or Imbellus, since every McK office can use one of these 3 standards.
  • Personal Experience Interview: fit and CV questions to assess your personal impact, leadership skills, and entrepreneurial spirit. You should prepare impactful stories about your experiences that cover these 3 main pillars.
  • Case Interview: typical business case to evaluate your structure in approaching problems, problem-solving skills, and business sense. This is the most time-demanding aspect to work on. I recommend reading Cosentino's Case in point to fix the theory. Then, what will be really important is practicing mock cases with other candidates here on Preplounge. (1-2 months full time will be enough)


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Content Creator
replied on Jun 18, 2019
#1 Coach for Sessions (4.500+) | 1.500+ 5-Star Reviews | Proven Success (➡ | Ex BCG | 10Y+ Coaching

Hi Anonymous,

it is not possible to provide an actual feedback just based on the weeks without more details. Many candidates need at least 100-150 hours starting from zero to get to a good level of preparation, however you could considerably reduce the time needed practicing with experienced peers and coaches. Thus, although theoretically 8-10 weeks could be enough, the answer in your specific case would depend on:

  • Your current level
  • How many hours of practice you could put in a day
  • Which support and material you would use for your preparation

Hope this helps,


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Anonymous replied on Aug 23, 2020

Dear A,

Preparation time can be estimated individually, considering your skills and competences. I would say, 8-10 weeks is an average time.

I recommend you start your preparation with reading Case In Point by Cosentino for a general understanding of what a consulting interview is. Then practise cases, some of them you can find in Case Library.

Once you feel you are not improving anymore, I would recommend you to take an expert coach for structured feedback and polishing your own performance.



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Alexander replied on Jun 18, 2019


You've gotten so much good feedback that it almost feels pointless to tack on. However, one thing that has not yet been mentioned is that you might have to pass a written test in addition to the actual interview. The test differs from company to company and from region to region. If you have a written test at your target company/office, you might have to dedicate serious time to it. This really depends on your background. If you search for "McKinsey PST", "BCG Potentials", and "Oliver Wyman Numerical Reasoning" you will find several examples.

Good luck!

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Ian gave the best answer


Content Creator
#1 BCG coach | MBB | Tier 2 | Digital, Tech, Platinion | 100% personal success rate (8/8) | 95% candidate success rate
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