Case Interview Overview

One of the most unique things about management consulting is its extensive use of “case interview” in recruitment processes. No, they don’t just ask you lame questions about your strengths and weaknesses. These are real businesses and real deals.
Let’s get pumped!

1

What is case interview?

To put it simply, case interview is a job interview with business contents. You will interact with an interviewer to analyze and hopefully solve case studies of business problems. That’s why it’s called “case interview”. In about 30 minutes (depending on firms and interviewers), you will replicate the course of actions real consultants do in real projects to solve the same business problem.

Here are some examples of business problems you may very well see in real case interviews:

    • Let’s say we have a restaurant called “In-and-out Burger” with recently falling profits. How can you help?
    • “The CEO of a cement company wants to close one of its plants. Should they do it?”
    • “A Top 20 bank wants to become a top 5. How can the bank achieve that goal?”

Along the interview, you will be assessed with the ability to think analytically, probe appropriate questions and make the most client-friendly pitches. Be noted that in case interview, your analytical thought process is more important than arriving at correct answers.

(See also: Consulting Interview Prep – How to prepare for Consulting Cases; How to avoid getting stuck in cases?)

2

Two formats of case interview

As different firms have different cultures, the specific formats and characteristics of cases vary firm by firm. There are many possible ways to classify cases. But for the scope of this article, I would like to mention the most important and helpful one: Candidate-led vs Interviewer-led. There is no clear border, but most case interviews rather fall somewhere in-between. But for the sake of study, going into the two extreme end of the spectrum is helpful.

On this extreme end, the interviewer rarely intervenes, and the candidate will lead the approach, from structuring the problem, drawing frameworks, asking for data, synthesizing findings to proposing solutions. This format can be difficult to beginners but it provides you much control over the case. For more advanced candidates, this is very comfortable as methodology is emphasized over results. And you know what, once you have that methodology (a.k.a: techniques) installed deep insight you, you can’t help but always score perfect, no matter the case, the problem, the result, etc.

On this extreme end, the interviewer controls the process in significant ways. He or she has the candidate work on specific parts of the overall problem and sometimes disregard the natural flow of the case. The game here is not to solve the one big problem, but rather to every question, every pitch, every mini-case perfectly. Because the evaluation is done on question basis, the level of insightfulness (a.k.a: Business Intuition) required is higher.

But like I said, most cases fall somewhere in the middle of the spectrum, so you need to master both formats. Don’t worry, we got yah covered!

3

The cornerstone of Candidate-led cases is the Fundamentals of consulting problem solving

“Problem Solving” is almost a buzz word in the consulting world nowadays. You will for sure hear a lot of them inside consulting firms’ doors. So what’s about it? What is so special that makes that word so magical?

“Problem Solving” in my simple language is: how management consultants solve problems! It is vital that you approach Case Interviews with the foundation of consulting problem solving. Let’s explore!

Every case / project starts with a Problem and it must be super well defined.

A good method doesn’t fix the symptom, but rather looks for the Root-cause and solve it. That ensures we have completely eradicated the problem and the impact is long lasting.

Bad method
Good Method

There could be thousands of possible Root-causes. In order to examine all while not missing any single possible one, we need a good system which we called “Issue Tree”. With this, we group possible root-causes into big groups. Those big groups will have smaller sub-groups in the lower level and so on. All the grouping is done in the spirit of MECE.

MECE: MECE is the standard of breaking problems down that all consultants try to comply. MECE stands for Mutually Exclusive and Collectively Exhaustive … which in simple language just mean 2 things:

Now that we have a few good branches in the issue tree, the task now is to test each branch to see if root-cause is indeed in that branch. Where to begin? Hypothesis helps here. We typically make an educated guess on which branch has the highest chance of containing the root-cause, and go test it. This action is called hypothesizing!

Now that we decide to test branch A, how do we do that? We try to prove or disprove our hypothesis by collecting DATA. That data is then compared with benchmarks to shed more meaning. Two main types of benchmarks is: historical and competitive.

Can the data prove the intial hypothesis true?

  • If the test says “NO”, eliminate that branch and go to the next one.
  • If the test says “YES”, go deeper into that branch, drill down to the lower levels until we identify all proven root-causes.

With all proven root-causes identified, the last steps is to come up with solutions to kill the problem … and we are done!

4

The cornerstone of Interviewer-led cases is to master question types

In interviewer-led case, the key to success actually lies in you effectively and elegantly nail all single questions the interviewer throws at you. You can treat each question like each mini case on its own. The best study method here is to tackle and study each question type. Click on the specific link below to find out more.

Here is the wonderful list of the most common case interview questions, ranked by popularity.

1. Math Word Problem

Everything stays the same, how many more units do we need to sell to triple the profit?

2. Guesstimate / Market-sizing

What’s the global market size in $US of smart watch products?

3. Issue Tree / Framework

What factors would you consider in tackling this problem?

4. Solution Finding

Given these root-causes you identified, what should the company do about it?

5. Data-Chart Insights

What insights could you draw from examining this Exhibit?

6. Value Proposition

What factors do customers look for in choosing between smart watches?

7. Business Valuation

How much does this company worth today?

8. Hypothesis

What are some possible factors that explain this trend?

9. Brain Teaser

What makes this number unique — 8,549,176,320?

5

The cornerstone of Interviewer-led cases is to master question types

Now stepping out of the picture for a little bit … besides a thorough understanding of problem solving fundamentals and major case questions …, what is needed to succeed with Case Interview?

To me, I like to think of this through 3 equally important factors: Techniques, Intuition, and Math.

No.1: Case Interview “Tips and Techniques” helps you show your structured approach, ask for timeouts at the right times, get clarifications when needed, deliver your pitches, to even organize your notes, etc. Think of this as the basketball shooting techniques that includes forms of hand, feet, body, etc. These are skills and habits that are learnable if you have the right materials and a good study plan.

No.2: Business Intuition on the other hand is like your natural sense of the business world, how to be insightful and creative in various business contexts, how to feed the “content” into your approach, etc. Think of this as a basketball player trains for muscle strength, agility, or durability. Intuition can be improved gradually through constantly exposing yourselves to a wide ranges of business situations and contexts. Of the three factors, this one is probably the hardest and may take the longest time to prepare for.

No.3: Consulting Math is simply how well you can deal with the quantitative side of cases

6

Now what? Step by step

If this is actually your very first case interview lesson, you may be wondering what are some of the next steps you should take for your study. So here are some advices for you:

1. Get a sense of case interview by watching sample case interview

See or read some sample case interviews in action to connect what you learn in this video with a real demonstration.
You may find this in our later videos, on consulting firms’ websites, or in various other prep materials. No need to do a mock case interview at this point. It can be very frustrating and discouraging if you haven’t got the basics yet.

2. Gradually build up your business intuition

Develop the habit of reading business publications to improve your business intuition. The earlier you start doing this, the better.
There are many good sources of business publications, but I strongly recommend those from McKinseyBain, and BCG. Also, building good base knowledge of business, strategy, and fields can help. Check out some good base knowledge article on this website.

3. Sharpen your Math skills in the process …

Get started with your Math practice. Again, the sooner the better. Visit our Consulting Math Questions section for more information.

4. Master the Problem Solving Fundamentals before moving on …

Without this, your further practice with cases can be frustrating … you will easily get lost in case and hardly grasp where you are in the process. See the section above and the more detailed article.

5. Learn those Tips & Techniques

Now you are almost ready to take on the first mock interview. But one thing for sure can help is to get as much Tips and Techniques as possible. The better you perform on the first mock case, the more confidence you have to keep moving forward.

6. First mock interview

Only at this point should you do a mock case interview. Do it, reflect, study the area you don’t feel comfortable with, then go back and do a few more mock cases and keep the cycle going on.

After all, case interview is a very good simulation of real consulting works. What you learn today is what you will use in your entire consulting journey from preparing for recruitment to advancing at your firm.

This process is a difficult but fascinating one. My guarantee is that you will always become better if you pay sufficient effort. I am so thrilled to share, and this article is here as one of your first benefits. There are many more related videos, pages and blog posts to help boost your progress. Use this page as a navigating port for your adventure to more advanced materials throughout our website.

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