Case Interview 101 – What Case Interviews Are, Why Firms Use Them, and More

In previous posts, we’ve discussed interviews, resumes, and the general recruiting process. Today, we want to touch upon one of the most important but often overlooked aspects of the interview process – the case interview.

What is a case interview?

If there’s one question on the mind of every aspiring consulting applicant, it is this: what is a case interview? How is it set up? What am I being asked to do? And most important, how do I master it?

Put simply, a case interview is where you are asked to solve a business problem, on the fly, with limited information. There will always be math involved, and you’ll be expected to talk your interviewer through your calculations and thought and decision-making processes. The goal of the case interview isn’t necessarily to get you to solve the business problem – it’s to see if you can think like a consultant, whether you can think on your feet, if the numbers you produce are logical, and if you can be trusted to communicate key insights in front of a CEO client.

There are four basic frameworks that all case interview problems can be categorized under:

Profitability, Market Sizing, Market Study, and Mergers & Acquisitions. These are general frameworks, but do a good job of organizing the main kinds of problems consultants solve on a project-to-project basis, and thus the types of problems that are presented in case interviews.

Profitability cases generally deal with a client trying to decide what to with revenues, costs, or overall revenue.  Market Sizing cases examine the size of a current market (usually in revenue), while Market Study cases examine whether a client should enter a new market or not, as well as the declining market share of a client.  Finally, there are M&A cases. These are the big boys of case problems, as M&A cases include Profitability, Market Sizing, and Market Study concepts all in one case. These cases are all about whether Company A should merge with Company B, or whether Company Y should acquire Company Z. Remember the one overarching goal of both of these transactions, though: increased profitability for the client!

Why do consulting firms use case interviews?

Because doing well in cases requires the same skills that consultants use:

  • Understanding of basic business concepts (e.g., revenues and costs, suppliers and customers, market structure, etc.)
  • Analytical, structured-thinking
  • Business-oriented creativity and insight
  • Communication and presentation

A case study mirrors the work that consultants do day-to-day.

What should I do to prepare myself for case interviews?

There’s no magic bullet for preparing for the case interview – it’s going to take grit, perseverance, and good old fashioned hard work. However, there are case study interview tips that will help you focus your approach:

  • Practice as much as possible with friends, colleagues, contacts within consulting firms. Even practice in front of a mirror to assess your communication style, body language, etc. Out loud practice is the key.
  • Review case study-specific resources – from the Vault Guides to Cosentino’s Case in Point. Don’t go overboard (in particular, Cosentino’s guide is helpful but not a must-have).
  • Go through our consulting-specific prep courses, and work with our expert MBB coaches.
  • Review general business problems – get your hands on as many case studies as possible. Most consulting firms post a few online, such as McKinsey here. The more exposure you have, the more familiar each question will seem. Even when you’re reading the Wall Street Journal, Fortune, etc. – put yourself into the CEO’s shoes at every opportunity.

Further reading: 2 smartest case study techniques and case study interview tips

We released a guide on case studies and consulting interview questions. Click here to check it out!

I’m not that good at case interviews. Can I get an offer by conquering the “fit questions” and my resume?

No. Your performance on case studies accounts for at least 50% (and usually more) of your “score” in determining offers. It is the most underprepared area for candidates, but something the best applicants excel at. If you want an offer, you’ll practice, practice, practice.

Case Interview Questions

So what does a case interview question look like, anyway?

If you’ve never seen a case interview prompt before, the whole process can sound very intimidating. Let’s demystify it a little bit – here’s a sample case interview question you’d see for each basic framework:

Market Sizing: Estimate the number of gas stations in Chicago.

Profitability: Your client is a well-known beer company. The company manufactures and sells beer. It is sold in pubs/restaurants and in bottles/cans (supermarkets, grocery stores, etc.), but mainly in pubs/restaurants. Recently, the client has become aware that profits have been declining while those of their main competitors have been increasing. Where would you start to solve this problem?

Market Study: A small life-science technology startup, One for the Road, Inc. (ORI), has invested a huge amount of money in R&D and was recently granted a patent for a new breakthrough patent. The client wants to know what approach it should take to commercialize the product.

M&A: Companies All Liquorice (AL) and Black Delight (BD) are both in the candy industry in the UK. The candy industry produces chocolate, liquorice, and chewing gum. There are 4 players in the market. Besides AL and BD, there is Chewin, the market leader and most profitable company, and Devotion. The market is competitive and strong consolidation has taken place over the last years. Now the Board of All Liquorice wants to acquire Black Delight. Why do you think they want to acquire Black Delight?

Non-standard case interview questions

I’ve heard that some companies/interviewers don’t ask standard case questions. Instead, they ask questions like “How many golf balls would fit into a 747?” or “How would you rescue the auto industry today?

That will happen, particularly in later rounds and with more senior interviewers. They may not be prepared to run you through a standard case, or they may want to see how you handle the unexpected. One question we faced (not at McKinsey but another firm) was the following:

Can you explain why Starbucks actively promotes the construction of locations that are so close to each other that they cannibalize sales?

If this happens, don’t panic. The interviewer is still looking for the same things – how crisp and logical is your thinking; how well do you communicate those thoughts; and how much do you understand the basic business underpinnings.

Further reading:

We give you tons more info on the case study interview, sizing questions, and fit/experiential interview questions in The Consulting Bible. With 300+ power-packed pages – including 16 case studies with exhibits – you’ll jump ahead of your competition with this top global resource on consulting interviews.

For more information on case interview resources, contact us today!

Click here to buy now and start landing consulting jobs!

  • Holmes5

    Do you know if there is a nice book to study cases?
    I enjoy reading your posts, Kevin

  • kgao

    @Holmes5 – I would recommend the Vault Guide to the Case Interview and Marc Cosentino’s Case in Point. Both are worth a summary read, but the best practice would be working through cases by yourself, with friends, and with people who’ve done it before.

  • Holmes5

    Thanks Kevin. Sorry, I didn’t want you to repeat one of your sentences, but I thought there were more interesting books on cases.

  • Weijiang

    Hi kevin,

    could I ask what was the answer they were looking for to the starbucks question?

  • cgdm

    you don’t sit and spend time in starbucks.
    you wait in the line, get your order and leave..
    generally starbucks’ locate in high populated places, so there is possibly be a long waiting line.. so they locate many shops so people doesn’t have to wait long..

    this is my opinion..

  • David Hama

    The question about Starbucks is interesting.
    I would think that for example Starbucks tries to suggest that people do not want to cross the street for something so essential as a morning coffee. Therefore this would explain why they might build two stores just opposite each other (which is quite frequent from my own experience).
    ….in the end of the day it all depends on your logic, communication and great synthesis….

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  • Boh

    I would think that there would be at least two issues in relation to the Starbucks questions:

    1) It is not a decided factor that sales are being canabalised because at the same time, you are getting additional customers (eg from other non-starbuck coffee stores, or ones who would not have for one reason or other gone to another store). Essentially, a new store would be giving additonal returns if the value of [net profit from new store] – [profit canabalised from another store] is positive.

    2) Having more stores, and generally being convenient, is a form of marketing for the brand of starbucks, so why not make a profit and market your brand at the same time.

  • RMP

    Quick question:

    Do consultants typically work on Saturdays? Sundays? or does it vary from firm to firm and from case to case?
    Any ideas?

  • Nicole . Carter

    Would anyone be so kind to tell me how i can find business case study practice questions. I need them urgently. Please do help.

    Thank you so much.

  • Hi RMP – from my experience, most consultants do not work, MOST of the time, on weekends. This of course varies firm to firm, case to case, and even consultant to consultant (it’s all about how effectively you manage your own time). The reason why I say “most of the time” is because occasionally, you can expect to do a bit of work over the weekends given project deadlines, emergencies that you cannot plan for, etc. Hope that helps!

  • Hi Nicole, aside from the Consulting Bible which as multiple cases in it, the best places to find practice case study questions would be:

    -Consulting firm websites (eg,,, etc)
    -Other interview prep resources such as Vault and Wetfeet
    -University consulting club websites

    …and so on. I will also be compiling a large list of these case studies to give away for free, so please be on the lookout for that. Thanks!

  • Nicole . Carter

    Hi Kevin, thank you so much!! I will keep an eye on the list you are compiling! :)

    Thank you so much once again!!

  • About Starbucks:

    I think they’d much rather compete with themselves and over saturate the market with their own brand, than compete with Carribeau or other Chains. The cost between opening an additional chain vs. losing business to a competitor probably makes the decision easy. Also, it leaves them to focus on their business in the area, and not their competitors.

    Additionally, they can leverage their resources between shops. Whether that is Baristas or Beans, having multiple chains in the area allows them to implement their labor resources (managers and baristas) and inventory in a manner that would be benneficial. Working at Starbucks looks pretty streamlined, and pumping coffee at one is the same as working at another. You don’t have to worry as much about how many people you employee at each individual shop, and how efficient you are being at a specific location if you can send resources to different locations.

    Also, Starbucks built their brand on convenience. The answer might be as simple as what was previously offered: “people dont’ want to cross the street.”

    And, on top of everything, the areas where you see multiple Starbuckses are ones where a lot of people are – particularly where a lot of businesses are. As a real estate investment, having property in the area makes sense. If it fails, then you still have the property.

    Also, I’m not sure how much it costs to close a starbucks (after accounting for selling off resources and land), but I imagine the returns made from one succeeding makes the decision easy.

    I also agree with the comment about the store as an advertisement. It’s not like they spend money on billboards, print or television ads. Same reason why they charge you less for using their special thermo cups with their logo on it. (at least that’s what I think they do.)

    So: cost/benefit between competing with yourself vs. true-competitor, leveraging resources, high traffic areas make good investments anyways, cost/benefit between succeeding and failing.

    Am I right?

    (anyone else find this news about them telling baristas to spend more time steaming milk or whatever? I feel like that was a mini-advertisement packaged as news. “Try the ALL-NEW Cup-o-Joe by Starbucks w/FRESH-Steamed Milk”)

    Sorry for turning this into a starbucks strategy forum

  • Chris P., I love your response and the clear way you framed it! Your answer is actually one of the better ones I’ve seen. I think aside from the strategic reasons for why (resource sharing, real estate investment, brand saturation, etc), there are clear financial reasons as well.

    From a company’s perspective, as long as they can: 1) grow topline revenues and 2) maintain or expand operating margins, then a decision such as this one makes sense. Since Starbucks is not franchised, it’s a much simpler decision for them to make in this case.

    Great discussion, guys. I may end up writing a post leveraging all of these comments.

  • samira

    hi, Kevin, i saw your posts, could you please provide me your list as well,
    i appreciate
    thank you very much

  • mrs D

    Help please has anyone completed the dominos pizza case study

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  • Eesha

    Hi Kevin

    I purchased your book and have finished practising the cases given there. It is undoubtedly a great resource but I need more cases to practice.Could you please let me know when will you be coming out with your list of cases?

    Eagerly waiting for it as my interviews are fast approaching.

  • Jane

    I think it is because the company has done research on how much time a person is willing to wait in line before deciding against spending $4 for a cup of coffee, so if they want to capture that revenue stream, they need to provide quick service. They know where the high traffic areas are and saturate the market with opportunities to purchase their product with no need to go elsewhere…or change your mind.

  • Ron

    Coming from a science (biotech) background, how would one maneuver cases like this (Starbucks) without referring to specific business terms, metrics and strategies? While I came up with similar ideas as the ones posted, without the technical jargon, am I at a disadvantage? I was under the impression that MC firms hire from a wide spectrum of background, so how important is the emphasis on approaching these cases with a business/finance lexicon?

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  • Eddie M Campbell

    I have a final interview in 2 weeks.  Are there any places where I can find free case studies to use for practice?  I am interviewing for a Sr. Sourcing Analyst position.

  • Dre60

    Where can I find case studies on Strategy and business Development in the Asset Management industry?

  • Saudiravi


             1. Was the suspension fair?       

    Did Joan act responsibly?

    Should she be fired?

  • kumar

    what about financial management pls cal me on 9372197030

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  • jennyrae

    Hi – which firms are these questions for?

  • Lakesh kumar

    where is this case answer pls reply me on a this mail id of this case answer

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  • Sgarulkumar88

    if u have the answer means, can u send that to the bellow mail

  • Prabhjot Singh

    i have done B.Tech from P.T.U (Punjab Technical University).Now I am getting job in iphone. They will give me 12000/mth. So my mind is confused that have i do Job or MBA from good university by giving the CAT Exam. But i have to drop one year.

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  • Fomuta

    Hi there, I am Tita AF. plse, can anyone help me. I am completing an online application form for junior economics consultant with one economics firm. They have asked me the Question: How many bicycles are there in South Africa?Please, show your assumptions and working. (75 words)

  • jennyrae

    There are countless of case studies online, but you have to search carefully for good ones for practicing, and they may not always include answers. We recently launched our Consulting Case Bank which is an online platform containing 550+ cases and PSTs from 25+ firms and 6 regions. You can search by firm name, case type, and more. Check it out on our pricing page, and feel free to contact us with any other questions you may have.

  • jennyrae

    Can you post a more specific question or request that you may have at this stage in your journey? We would love to respond. You also can feel free to e-mail us directly through our Contact Form at the top of the page.

  • jennyrae

    Are you still thinking over what your next step should be? Contact us directly using the form at the top of the page. We’d love to offer advice if needed, relating to your overall future goals.

  • jennyrae

    Great question. The two places we would start would be firm websites and our case bank.

  • brutal

    go for MBA!!!!!!!!!!!!!!!!!

  • Cuselone

    These are all helpful stuffs that would help in every aspiring educators to have an excellent way to become a consultant. That things you have stated here was clearly understandable. Thank you for sharing the good tips in here.

  • ejaz khan

    hi g..i hve one medical case
    an woman of 33 year old mother of 2 child has approched to nurses that she is feeling hungry frm last 3 months while she eats more and also lost 10 kg weight,she is experencing repeat episod of diarrhea and often feel nauseated,aslo feel weekness and anxious..her vital sign
    temp 38 c
    pluse 110 bmp
    bp 150/90mmhg,
    physical finding shown that she has swelling in neck,she has also compalined in voice.complain of not full closing eyes..she feel full sweat as ac presnt
    what is the patient likely to suffering from?
    what assessment find u to support urs hypothesis?
    any additional assessment question requried?
    how can u help the patient over all managment?
    what will b surgical intervention for her related to nursing?
    develop nursing care plane relate to health education

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