Case Interviews: Advice from a senior

By Xiangrun Li   •   10 min read

Despite the ‘upheaval’ in the financial markets of 2007s during the global crisis, the Euro sovereign debt crisis which peaked in 2010 – 2012, and the current COVID-19 crisis, one industry has been particularly resilient — Management Consulting.

The management consulting firms are famed for their friendly and collegial culture with talents having extensive industry experience and functional expertise to help deliver customised solutions and to help drive tangible results for their clients.

Both Sharon (Co-founder of TalentTribe) and I had made it through various rounds of consulting interviews and had received job offers from ‘MBB’ (McKinsey, BCG, Bain & Co) previously, and thought that we can share some background on how one can prepare for their management consulting interviews.

Besides the de rigueur academic requirements and demonstrated background in ‘strategy’ work via school and internships, how do you prepare yourself once you land a chance to be interviewed?


A management consulting firm’s typical approach to interview is the typical market sizing & case analysis. Just go in with a clear brain & be ready to do some quick thinking. Present your solutions in a clear and concise manner with a strong logical thought-flow & structure.

Be prepared to answer brainteaser questions at the end of the case interview where the interviewer would ask out-of-the-box questions like how many cubes do you take away from a 10x10x10 cube to arrive at 9x9x9?


1. Introduction 

A typical case interview lasts about 45 minutes. About 5 to 10 minutes is taken up with preliminary chat and behavioural questions, followed by 25 to 35 minutes for the actual case interview question or questions, and finally about five minutes of you asking questions about the company.

To prepare for case interviews, it’s useful to first understand the structure of the case interviews.

During the case interview, your interviewer will present you with a business problem and ask you for your opinion. Your job is to ask the interviewer logical questions that will permit you to make a detailed recommendation.

The majority of case interviewers don’t have a specific answer they are looking for. What the interviewer is looking for is a thought process that is both analytical and creative (what consultants love to call “out-of-the-box” thinking). Specific knowledge of the industry covered by the case question is a bonus, not a necessity. Typically, business school students receive case questions that require a deeper understanding of business models and processes.

I have structured this article into 3 parts: In the first part, I will introduce to you the few types of case interviews. This is followed by samples of case questions to give you a feel of how the case interview is executed. The last part is a list of recommended reading materials to prepare you for the case interviews.

2. Type of case interviews 

Case interviews are not designed to explore educational, professional, or experiential qualifications. If you’ve reached the case interview stage, take a deep breath – the consulting firm has already weighed your background, GPA, and experience and found you worthy of a deeper skill assessment.

It is now a matter of acing the case interviews to get the job offer.

Case interviews vary widely, but in general they fall into three groups: business cases, guesstimates, and brainteasers.

Because this serves as a quick guide, we will focus on covering the fundamentals of a case interview. Acing a case interview requires us to go a lot more in depth, which will be explained thoroughly in another article called How To Ace Case Interviews.


2.1. Case Interviews 

Case interviews vary somewhat in their format. The classic is the business case, in which you’re presented with a business scenario and asked to analyse it and make recommendations. These cases will always require you to drive to a conclusion.

Most cases are presented verbally, though some involve handouts or slides. Remember to read What Are Case Interviews & How To Answer Them to pick up some basic frameworks from there.

However, it is important to avoid blindly regurgitating the frameworks (4Ps, Porters’ Five Forces, etc). Instead, apply the frameworks to the context of the case in your analysis without making specific references to them.

That being said, do use the typical frameworks if it is easier for you. The usage of extremely basic frameworks is acceptable (e.g. Internal / External analysis, Revenue – Cost = Profit analysis) because it allows you to branch deeper into the analysis of the issues.


2.2. Guesstimates 

Whether free-standing or as part of a case, learning how to make “back-of-the-envelope” calculations (rough, yet highly accurate) is an essential part of the case interview.

As part of a guesstimate question, you may be asked to estimate how many bottles of beer are sold in Singapore each year, or what is the market size for a new consumer product. The guesstimate question may also be one step within a larger question. For example: You might need to figure out the market size for a specific software as a first step in determining whether or not the client should enter the European market (and if so, how the market entry should be done).

You will not be expected to get the exact number, but you should come close – hence the guesstimate. Non-business school students and others who appear to be weaker quantitatively may get stand-alone guesstimate questions independent of a case.

2.3. Brainteasers 

Brainteasers are normally logic puzzles or riddles. They may be timed. Often, brainteasers are meant to test both analytical and “out-of-the-box” thinking, as well as grace under pressure.


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3. Examples of Case Questions


3.1.  We have a client who is a leading player in the renovation business in Hong Kong. They provide residential renovations, home building, home improvements, etc. This client is trying to decide if it should go into doors, specifically wooden doors for homes. Tell us what you think the market size for wooden doors would be. Is it big enough to be attractive?

Let’s talk through the logic of how you would evaluate whether or not our client should enter this market. Take your time before answering.

Typically, you begin this question by doing a 10-15-minutes “estimation exercise”, which consists of questions such as:

  • How many doors are there in the Hong Kong?
  • What’s the market for wooden doors in the Hong Kong?

After asking questions like these, you should be able to come up with a rough estimate. You will usually be provided with paper and pen, which you can use to jot down ideas, keep track of your thoughts, or do quick calculations.

  • For the next 20 – 25 minutes, you should talk about the issues that the company might be thinking about before entering the market, by asking questions such as:
  • Competition: What is the competition like in the market?
  • Company: How will the manufacturing of wooden doors affect the company’s labour costs? What is the capital expenditure required?
  • Customers:  What are the most profitable segments of the market?

Follow through with a well-structured thinking and then drive to a conclusion.


3.2. Our client, PT Coffins, is a coffin manufacturer in Indonesia. Up until now, the company has been in the business of building high-quality hand-crafted coffins largely by hand with a skilled labour force. Recently, however, the firm has become aware of technology that would allow the company to produce high-quality machine-made coffins with much less labour. Should the firm invest in this new technology?

The interviewer may just test your resourcefulness with a market sizing question. You can explore the following ways of market sizing:

  • Calculate the population growth, total population, and birth rate
  • Review death records for a period of time
  • Take sample of number of obituaries in paper serving given population base
  • Calculate from population the average life expectancy

Next, you should identify or request for information about the following points:

  • Investment: How much will the new technology cost the firm?
  • Cost Savings: What are the cost savings? Material costs may remain the same, but how much labour costs can we save?
  • Proprietary Nature of Technology: Is the new coffin-making technology being offered to our competitors also?
  • Competitive Threat: Will the competitors acquire this technology too? Are they looking to acquire it?
  • Customer Preference: What is the quality perceived by the customer for machine-made coffins? Is it the same or better?
  • Brand Impact: Will the switch to machine-made coffin negatively impact the brand?

You will then move on to the other parts of your analysis, practising the same approach as above to ask relevant and critical questions that will allow you to build your recommendation and conclusion.

As usual, summarise your analysis and drive towards a well-structured conclusion.


3.3. Your client, “CanadaCo”, is the largest discount retailer in Canada, with 500 stores spread throughout the country. For several years running, CanadaCo has surpassed the second largest Canadian retailer (which has 300 stores) in both relative market share and profitability. However, the largest discount retailer in the United States, “USCo”, has just bought out CanadaCo’s competition and is planning to convert all 300 stores into USCo stores. The CEO of CanadaCo is quite perturbed by this turn of events, and asks you the following questions: “Should I be worried? How should I react?” How would you advise the CEO?

This case interview is taken from one of the MBB’s website. Essentially, the interviewer is looking for you to ask many questions.


  • What is a discount retailer?
  • Are USCo’s strengths transferable to Canada?
  • Do the product mix of the stores differ?
  • What is each company’s cost structure?


  • Is the Canadian market comparable to the US market?
  • What is the consumption trend in Canada? Is there an increasing market or untapped market in the discounter segment?
  • What geographic markets do CanadaCo’s competitor stores serve?

The key is not getting the ‘right’ answer, but showing you can think in a structured fashion.


3.4. Walk me through the operations of a typical Starbucks. How might they increase their profitability?

Utilise the frameworks to structure your thoughts and walk the interviewers through your analysis.


3.5. Guesstimate: How many traffic lights are there in Singapore? (h3)

This guesstimate can be calculated in numerous ways, including estimating the number of Singapore street corners and assuming one traffic light per intersection, coupled with the estimates on the traffic lights along roads with pedestrian crossings in housing estates or near the schools.

Another method would be to estimate the length of the road network in Singapore and assume one traffic light per X kilometre. Don’t forget to illustrate that you’ve excluded expressways when calculating the length of the road network!

You’d probably receive this question in conjunction with a case on an industrial manufacturer that is thinking of bidding and entering the traffic light market.


4. Further Readings & Preparation

4.1. Reading Guide

You should make use of your university’s subscription to publications such as ‘Wetfeet – Ace Your Consulting Interviews’ to prepare for your case interviews.

I will advise that you find a case partner to practice the case with you as continuous reading of additional cases like a textbook will not add much value to the learning.

4.2 Preparation is key 

I believe that with sufficient preparation, you will be able to tackle all sorts of case interviews confidently. Some of the key characteristics that consulting firms look for are analytical skills, quantitative skills, interpersonal skills and intellectual curiosity.

Do demonstrate these characteristics (and other positive ones) during the interview.

At the end of the day, you are not expected to know the technical aspects of every industry for the case interview. It is more important to demonstrate your logical thought-flow and structuring the problem in a clear framework, as well as asking the right types of questions to analyse and solve the case.

With that, you’re good to go!


If you thought that was helpful, you’re in for a pleasant surprise.

We’ve collated insider secrets and answers to questions you will definitely have about management consulting – all in “The Ultimate Starter Guide To Management Consulting”.

Hear it for yourself from ex-consultants and consultants from the big firms in the industry like McKinsey, BCG, Bain & Co., Oliver Wyman, & more.


Xiangrun Li

TalentTribe Writer

Xiangrun Li has worked in investment banking for more than a decade, advising corporates on capital raisings and mergers & acquisitions. Prior to embarking on his corporate finance career, he had worked on multiple internships across equity research, fixed income investments and management consulting. A budding programmer, Xiangrun is also active in the Fintech and startup space. When he is not tinkering with the financial models, Xiangrun enjoys a good stretch on the yoga mat. Xiangrun holds a Masters of Science in Global Finance from NYU Stern & HKUST and a Bachelor of Science in Economics from SMU.


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