How many mock cases until I am "ready"?

Anonymous C asked on Mar 08, 2018 - 11 answers

Hi all,

I wonder how many cases candidates typically need to solve before they are "ready" for the real case interview at the big firms? How many hours of practice should I expect before considering myself good enough to show up at McKinsey et al.?

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Originally answered:

AM I DOING ENOUGH LIVE CASES?

Best Answer
Tyrion Lannister replied on Jul 10, 2018
High-borns only! Targaryens preferred. Absolutely NO Lannisters! :-)

Are you a proud member of the Cabal of Case Commandos? Let’s have a frank and thoughtful conversation about this.

When I look through PrepLounge’s Meeting Board on any given day, I am struck by a particular sub-set of candidates who, by a very specific criterion, stand head and shoulders above the rest of the pack.

In this specific criterion, they are the clear leaders!

I would even go so far as to say they’re the envy of fellow PrepLounge peers.

Perhaps some of you even aspire to join their ranks?

I refer, of course, to those PrepLounge candidates who have accrued hundreds and hundreds of interviews over comparatively short time-frames.

Think about that for a moment: hundreds and hundreds of interviews.

This means these candidates have consumed hundreds and hundreds of Cases which they can never do again.

I’ll come back to this (which is the core of my arguments today) in a moment.

I wanted to pause and share an anecdote from a candidate within what I’m calling the Cabal of Case Commandos.

This candidate said: “I am aiming to solve at least 200 Cases before my interviews!”

When I probed for the motive behind this, all I could get was that he felt that 200 Live Cases simply represented the right number to crack his final interviews.

Guys, I could not disagree more!

I disagree not only with this magic number of 200 Live Cases as a preparatory pre-requisite, but also just more generally with this mentality that more is better.

I’d like to flip this question around and ask:

AM I DOING TOO MANY LIVE CASES?

My opinion is that too many candidates are!

As we answer this question together, let us explore:

+ the ultimate objectives of Case prep.

+ the limited availability of quality Cases

+ the magic number of Live Cases for a successful preparatory effort

Ultimate Objectives of Case Prep.

In my mind, there are three over-arching goals to doing Live Cases to prepare for final interviews:

  1. To become familiar with the unique interview format required to gain entry to a career track in Management Consulting
  2. To develop and demonstrate a superior skill set in problem-solving as it relates to complex questions in management and strategy
  3. To build up interview stamina across the core assessment metrics to be tested in the final interviews

Voila!

So, what does all this mean?

By the time most candidates come to PrepLounge, or acquire the leading literature on Case interview prep., or join a Consulting Club at one of the leading Business Schools, they are largely familiar with the Case interview format. It hardly takes more than 3-5 Live Cases to reinforce this.

So, the first ultimate objective (see above) is covered in 3-5 Cases.

Similarly, in the two or so weeks before your final interviews, you likely lean (and rightly so!) towards pacing yourselves with no more than five Cases per week (so, one a day with one or two rest days to focus on other areas of the preparatory effort) in order to keep your problem-solving skills sharpened; your energy levels and interview stamina up; and your tool kit of quantitative ability, logical structuring and synthesis, top-down and client-ready communication honed.

If you’re doing interviews across any number of firms over the course of a month, you can expect to do 20 Live Cases in this final stage.

So, we have 20 Cases to satisfy the third objective, and no more than 5 Cases to satisfy the first objective.

A grand total of 25.

If we go back to my Case Commando, we can then infer that he believes he needs 175 cases to attain and demonstrate a superior problem-solving skill set.

This number sounds waaaay too high to me!

I’ll explain.

Using the traditional MBA first year recruiting season as a reference for time-frame (a time-frame which I consider to be rather excellent both within and without the formal MBA recruiting calendar), most candidates have about four months (~16 weeks) from Day 0 to the end of the recruiting season. In many cases, that’s mid-September to late January.

If we strip out the first week (focused on objective 1) and the final 4 weeks (focused on objective 3), then, using Case Commando Carl’s objective of 200 Cases, we have 11 weeks in which to crack 175 Cases. That’s 16 Cases a week. More than 2 Cases a day. EVERY. SINGLE. DAY. For the next three months.

My explanation for why this sounds unreasonable is simply that it is quite difficult to extract quality learnings from a 3-month period in which you average 2+ Cases a day.

Preparation via Live Cases transcends well beyond the 35 minutes or so in which the Case is delivered and in which you proffer what you believe to be ‘the answer.’

An anatomy looks more like this:

Of the actual case;

  • 35 minutes: the Case is given
  • 15 minutes: your Case partner discusses the Case solution with you and provides quality feedback (if you’re Casing with people who aren’t doing this, find other Case Partners)
  • 20 minutes (at least): you reflect on the feedback you have received and reconcile it to your own self-assessment

The rest of the time is then spent on noting what strengths you displayed in that session and how you might play to them in future sessions (and, ultimately, your final interview), along with identifying what development areas are emerging. On the latter, you want to clearly understand what these are, seek out further resources to tackle them (for example, if you’re poor at top-down, synthesised communication, you might wish to seek out literature that provides winning tips to excel at this), and develop strategies to improve upon them.

This is an exercise that, in the early weeks at least, would take hours!

You then want to do a final assessment and set goals for your next session:

  • how can I be more intellectually rigorous in defining my initial hypothesis and problem-structuring?
  • what can I do to be a more effective communicator?
  • are there times I have missed opportunities to do sanity-checks in progress?

These are only examples, of course.

If you’re well into your Case prep., you ideally want to go back periodically and say:

here’s where I was two weeks ago:

+ good problem structuring

+ excellent quantitative manipulation

+ need more work on top-down communication

here’s where I was a week ago:

+ getting really comfortable with problem structuring (my regular Case partner who I trust says I’ve gotten better and am the best he has seen among his cohort)

+ still nailing even complex elements of quantitative manipulation

+ still need more work on communication

Self-Assessment

I NEED TO FOCUS ON RESOURCES FOR THIS WEEK THAT WILL IMPROVE MY COMMUNICATION AHEAD OF MY NEXT BATCH OF LIVE CASES.

Also, what advanced resources are there where I can practice my problem-structuring skills outside of Live Cases. This is clearly a strength of mine. I need to play it up hard!

This process then repeats itself as you go through the calendar, but already, some truth is emerging:

if we agree that the above represents an optimal way to approach the preparatory efforts, it is almost impossible to achieve any meaningful intellectual rigour at a steady clip of 2+ Live Cases every day for three months.

My take-away: an arbitrary (and rather high) number of Cases simply for their own sake will not get you the Offer.

Successfully applying a specific set of problem-solving and communications skills at a consistently high level will.

The key is to approach that high bar through a smart preparatory strategy that is anchored in measurable results that matter.

Limited Availability of Quality Cases

How many times have you done a Case (either Live or simply watched a YouTube clip of a real Case) and thought to yourself: well, that wasn’t a very good case?

In fact, I’d wager that quite a number of you have begun a Case that you eventually found so cumbersome, or so unrealistic, or so lengthy as to be counter-productive to your preparatory efforts that you gave up midway.

I can relate!

We all know an inconvenient truth: the number of quality Cases out there is slim, and the pipeline of new Cases is limited.

I do not have general numbers other than those available to me anecdotally from my own efforts, but, in spite of my monumental effort to source high-quality materials both online and off, I really only came across 50 or so good to really good Cases that positively contributed to my preparatory efforts:

McKinsey Cases: 5

BCG Cases: 7

Bain Cases: 5

Wharton Case Book: 10

Duke Case Book: 5

Rotman Case Book: 3

Case-in-Point Cases: 3

PrepLounge Cases: 4

Miscellaneous: 8

And once I did these Cases, I could never do them again.

I often came across Cases that I considered a waste of time, and others that were detrimental to my overall efforts. The last statement is important. For if I were Case Commando Carl, my 200 target would force me to waste my time and imperil my efforts about 75% of the time.

Now, I realise the 75% number is questionable (there are likely a great many more than the 50 or so good Cases I was able to find in my time), but the truth is not too far off.

Will you really have access to 100+ fantastic Cases in the period of four months or so?

Is it really wise to burn through good material as you seek to build up your number of Cases ‘solved’ at the risk of running out just as your Case strengths are emerging and you need quality material to challenge you?

I say the answer is No.

Conserve your jewels and use them wisely.

So, before I wrap this all up, what have I established?

Two things:

  1. That the finite Case prep calendar does not afford enough time to bring a consistent level of requisite intellectual rigour to 2+ Live Cases a day for a 3-month stretch, and
  2. That since the number of skill-building Cases does not approach 200, a plan to attempt 200 nevertheless becomes counterproductive (in my case, by what would have been a factor of 3:1)

Before we explore the third and final point in this argument, I’ll point out something else: each Live Case you tackle is only as good as the practice partner delivering it.

Are you sure you can find that cohort of trusted partners (in my time, I was only lucky to find six individuals whose Case delivery I admired, and whose feedback I found useful) who will each administer 30 Cases to you (that’s 180 good Cases if they can find them!) over a four-month period?

Magic Number of Live Cases for a Successful Preparatory Effort

Does such a number really exist?

I have good news friends: it doesn’t!

Do not complicate this already stressful exercise by introducing arbitrary targets that are meaningless.

If you achieve objectives 1 -3 (see above) in 50 Cases. Great!

If you need 90 Cases to reach that comfort level, that’s also great!

As long as you’re conscious of progress and have a clear bar you wish to attain, you will quickly realise as you traverse this path what the magic number of Live Cases should be for you.

Before I conclude on a short list of things you can start doing now to improve your preparatory efforts, I will share some unscientific data I collected during my time as a candidate.

  1. Of the candidates with 150+ interviews on their profile, 100% of them performed, when solving Live Cases with me, in the bottom half of my own assessment curve based on the complete set of all candidates with whom I practised. I am in no way claiming causation. But from the small sample set (and thankfully, it was quite small), I could see no exceptional brilliance for all the Cases they had done.
  2. Of the candidates with 150+ interviews on their profile, all but one of them were quite tedious to practise with. Their delivery was very textbook templated, their problem-structuring lacked imagination, and they relied excessively on traditional frameworks attempting to force them onto problems where they did not fit. They also employed lots of business jargon where such was not needed, and were altogether quite tiresome. In other words, they had become Case robots. No Consultant at an actual interview wants to assess a robot.
  3. Of the candidates with 150+ interviews on their profile, most had gone through every single Case I had prepared for them.

This can be a bit frustrating if you’ve prepared up to three good Cases (which is good practice for peer-to-peer practice, anyway) and find that they’ve done them all. The other half to Casing is to observe others do the same. By so doing, you may aspire to their strengths and learn from their errors. Case Commandos routinely rob you of this opportunity.

This is a conversation.

I have no accreditation to make ultimate claims one way or the other, but I can challenge behaviour that is demonstrably counter-productive to Case prep. efforts.

As you ponder these things (and, hopefully challenge any assertions of mine that lack merit), I would like to encourage you to step-up your Casing game with the following recommendations

For Partners

  1. Avoid Partners who have scheduled back-to-back-to-back sessions on the Meeting Board. A crucial component to Casing is to receiving perceptive, useful, and actionable feedback. Case Commando Carl who needs to rush off to his next session is hardly in a position to provide this.
  2. Hold on to every good Case Partner you can find. In my time, I Cased with over 40 unique individuals. Only six were able to consistently contribute to sessions at a very high standard. I courted these partners by, as much as possible, being available when they needed me, and even developing friendships. 6 great partners are better than 60 crappy ones.

For Cases

  1. Guard all your Cases jealously. The good ones are in such short supply. Get trusted partners to recommend good Case resources and try to administer Cases you have already done before ever venturing into Cases that are new for you.
  2. Set performance targets for yourself and measure your progress religiously over the key metrics that define Case interview success for you.

Good luck and good fortune in the wars to come!

Great post! Can you share the qualities of the six strong partners that you mentioned, e.g., what made them helpful? — Nick on Jul 10, 2018

Hey Nick. When I think of these individuals, different things made them stand out. The qualities most useful to me were: i) always coming to sessions well-prepared, and with back-up Cases just in case; ii) delivering feedback that was insightful, useful, and actionable, including not being afraid to give tough feedback; iii) serving as a benchmark for my performance progress (hey, you're better at this when we first started, or, you're still making that mistake I told you about); iv) being flexible (i.e., I'm super busy this week, but since your Decision Rounds are coming up, you have priority over everything I'm doing for the next 7 days; v) sharing useful practice resources beyond the Case (my first foray into the Victor Cheng Look Over My Shoulder was via a trusted Case partner). I have remained friends with four of them (close friends with three), and cannot thank them enough for their kindness. I hope that helps? — Tyrion Lannister on Jul 10, 2018

Thank you, this is very helpful! — Nick on Jul 10, 2018

Sidi
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replied on Mar 08, 2018
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What I have seen again and again is the following:

It is much more important to focus on quality, rather than quantity! If you fail to build the right routines and habits, the effect of more mock case will be actually detrimental at some point. So finding an outstanding partner or booking an expert should come very early in your process! This will allow you to double down on your problem areas from the start!

Most people that I helped getting into MBB reached a solid "offer-ready" level by the time they had solved about 30 full ~45 minutes cases with an experienced case partner (and also doing revisions after getting good feedback on every case).

Cheers, Sidi

This might be specific to BCG...I was on a call with BCG and they mentioned we should not loose sight of the fact that it is a conversation and they value creativity. That said, you want to practice the right way by not trying to memorize problems, but rather mastering how to approach problems, how to ask probing and clarifying questions, and how to think creatively. — IBRAHIM on Mar 08, 2018 (edited)

What are your thoughts on that Sidi? — IBRAHIM on Mar 08, 2018

Ibrahim, this is exactly what I mean! What you need to build is a methodic muscle regarding a bullet proof approach towards cases. It is not about memorizing! Creativity is always valued, and the best way to be creative is to brainstorm within a certain "thinking frame" - thereby one can generate much more ideas to literally any problem! — Sidi on Mar 08, 2018

Thanks Sidi! — IBRAHIM on Mar 08, 2018

Originally answered:

Number of cases

Guennael
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replied on Aug 12, 2016
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This is a great question, I see a lot of advice (even on MBB websites) suggesting you don't want to be over-prepared. Yet I think many of us who successfully get in end up studying well north of 50 to 70 hours; I spent well over 100 hours for example. Can you succeed with less? Sure, but why risk it? You will only have so many opportunities to apply: After undergrad, after you masters, and perhaps once or may be twice as an experienced hire.

Based on my experience, the most important factor is not the number of cases, but the time you spend getting ready: both how many hours (cf. 50+ hours above) and the number of days / weeks you allocate. I started preparing slowly a few months before I even applied, and really intensified it the last month. The last few weeks, I'd spend 2 or 3 hours a day practicing.

I believe there's one more thing that's extremely important beyond the time you spend studying or the number of cases you go though: the quality of your feedback. I just finished writing the below on another thread, and it is very applicable I believe so bear with me as I do a simple copy/paste:

My recommendation is such: do a (couple of) case(s) with a current/former consultant early on, and write down their feedback; practice on your own and with fellow applicants and work on the initial feedback; mid-way through your prep, perhaps do another case with a consultant to course-correct. Near the end, do one or two more cases w/ a consultant to make last-minute adjustments. All throughout, do 15-20 minutes of mental math and market sizing every day. Total prep time should be well above 50 hours over 4-6 weeks, don't hesitate to go over 100 hours like I did.

Look, I know some of you may think I am just talking my book and trying to convince you to spend money - no, I am not. I was lucky to have 5 friends at BCG when I applied, and each one of them gave me at least 2 cases (for free). But if I had not had these friends and had just studied on my own, odds are I wouldn't have made it, plain and simple. If you are in school, you probably have access to alumni or upper classmen/women who have at least done an internship and would be willing to help for free. If you do cannot find someone to help you, my honest opinion is, get ready to spend some money. Yes you can get in without this - but the odds would be stacked against you. It is a competition, spots are limited - and we always have a lot more qualified applicants than openings. Luck plays a role, but might as well be as prepared as possible -> At the end of the day, nothing can replace the feedback one of us current/former consultant can give you.

Good luck,

Guennael -

ex-BCG Dallas

Francesco
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replied on Mar 08, 2018
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Hi Anonymous,

I agree with Sidi on the general importance of quality over quantity. Consulting interview preparation is similar to going to the gym: you may even hurt yourself overtraining or focusing on the wrong elements, independently by the hours you put, while you can speed up your results with the right trainer/coach/partner.

To directly answer your question: the number of hours depends mainly on (i) your status before starting the preparation and (ii) what you use for the preparation; among the most relevant elements I would consider:

  • Initial business acumen level
  • Initial communication skills
  • Previous experience in structuring problems (eg consulting experience)
  • Ability to absorb new information
  • Quality of material/partner used for the preparation

Based on my experience, the range goes between 20 cases/ 30 hours (with experts/very advanced partners) and 100+ cases / 150+ hours (on our own/average partners).

Best,

Francesco

Originally answered:

How many case studies should I do?

Hemant
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replied on Apr 28, 2017
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Quality > Quantity. Focus on:

1. finding the right partner, and / or expert to work with.

2. focusing on your negatives maniacally and not making those mistakes again

3. read through as many generic (tier-2) cases as you can to build a mental database of what to do when, and then try to start solving the tier-1, more difficult cases

4. Typically I see good case solvers once they've done anywhere between 20-40 solid, difficult cases covering a range of industries and business problems

Vlad
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Hi,

It's more about quality rather than quantity:

  1. Don't count the cases you've done yourself
  2. Don't count the cases you've done from the casebooks
  3. Count the cases you've done with experienced candidates (50+ cases solved / passed the first round) who can give you a real case and a good feedback.

In that case, you need 40-50 cases depending on the role, office, etc (e.g. MBAs in top schools need just a bit of practice compared to regular candidates. Both because of their knowledge and because the on-campus hiring is not that tough)

If you take a good coach, you can make it in 20-35 cases. The coach will give you the right knowledge. Partners will help you integrate the skill. At the end of the day, it's just a skill that can be trained.

Why do you even need partners and coaches? When you are stressed during the case interview and out of energy having the 3rd case in a row, 90% of your questions and reactions should be fully automatic. Otherwise, it's extremely hard to solve the case, trying in find out what you've memorized from v.Cheng book.

Best!

Originally answered:

Number of cases

Ben replied on Aug 18, 2016

short answer - yeah. after you've done 100, other than the bare minimum to stay sharp there isn't much point... its just going to stress you out

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