Table of content
Case interview 101 – The online guidebook
“Case Interview” is the cornerstone of consulting recruitment, playing a decisive role in final results. In 30 minutes, your “consulting” qualities will be tested to the limit as you cruise through a hypothetical “consulting project” with the interviewer.
Yes, this is a BIG topic. The depth of content in this single article is HUGE with various chapters ranging from beginner’s topics to more advanced ones. You would want to bookmark this page and go back often throughout your whole preparation journey.
What is a case interview?
A case interview is a job interview where the candidate is asked to solve a business problem. They are often used by consulting firms, and are among the hardest job interviews, testing both problem-solving skills and “soft” skills. Case interviews often last 30-45 minutes each, and firms can utilize up to 6 case interviews, usually divided into 2 rounds.
Example case questions:
Case interview are modelled after the course of actions real consultants do in real projects – so success in case interviews is seen by consulting firms as a (partial) indication of a good management consultant.
Along the interview, the interviewer will assess your ability to think analytically, probe appropriate questions, and make the most client-friendly pitches. Be noted that the analytical thought process is more important than arriving at correct answers.
Generally, there are 2 styles of conducting case: Candidate-led and Interviewer-led.
On this end, the interviewer rarely intervenes; 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 for beginners but it provides you much control over the case.
On this 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 nail every question, every pitch, every mini-case perfectly. Because the evaluation is done on question basis, the level of insightfulness required is higher.
Most cases will fall somewhere in the middle section of that spectrum, but for education purposes, we need to learn case interviews from both extreme ends.
Great details in each and every aspect of the case, as well as tips, techniques and study plans are coming in the chapters below. You may skip straight to Chapter 3 if you have business background and confident in your own understanding of the terminology used in case interviews.
To better understand or practice candidate-led and interview-led cases, let’s book a personal meeting with our coaches. At MConsultingPrep, you can connect with consulting experts who will help you learn the ins and outs of both cases and the solving approach to each one. Get “real” practice now!
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Case interview starter guide for non-business students
All consulting firms claim that all educational backgrounds have equal chances. But no matter what, case interview reflects real-life business problems and you will, therefore, come across business concepts.
Not everybody has the time to go to a full Business Undergraduate program all over. So through this compact Chapter 2, I will provide you, the non-business people, every business concept you need in case interviews.
Accounting and financial terms – The language of business
Accounting & Financial Terms are often called the language of business, which is used to communicate the firm’s financial and economic information to external parties such as shareholders and creditors.
There are three basic financial statements: Balance Sheet, Income Statement, and Cash Flow Statement.
A snapshot of the current stage of the company’s property, debt, and ownership at one given point in time, showing:
The neat thing about the Balance sheet is that it’s always balanced. Every action, every transaction changes the three components but it’s always in harmony.
A record of the business performance through a period of time, given it a quarter or a year. The Income Statement directly tells you how the company is doing in terms of making money, the heart of any business.
From the top to bottom, the Income Statement shows the Revenues, Costs, and Profits. That’s why often, Profits is referred to as the “bottom line”.
There are a few types of cost to notice – see the two pictures below this table.
One important thing to notice is that even though it may seem like, the Income Statement does NOT necessarily relate to cash. Many of the times, especially for B2B transactions, the selling happens before the money flow. Therefore, we may have to record revenue without having the cash.
Cash Flow Statement
There’s a famous saying that: Income statement is an opinion, Cash Flow statement is the fact.
The Cash Flow statement just strictly monitors the cash flow in or out, categorized in different sections. Three of them are:
Upon completion this section, you should be able to read and interpret financial statements for business diagnosis and decision-making.
More importantly, you possess the conceptual base to start solving case interviews on your own. Do not forget that, as with any other language, becoming proficient with accounting and financial terms require constant practice.
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Organizational structure – The heart of a company
When it comes to organizational structure, it is important to notice the fine line between the company’s ownership and management.
Technically, at the highest level, there are shareholders. For private companies, the group of shareholders and their shares are not necessarily disclosed and publicly tradable. For public companies, on the other hand, shares are publicly traded on different stock exchanges. One of the most famous is the NYSE, which stands for New York Stock Exchange.
Below CEOs, there are two generally two ways of structuring the company. One way is through business lines and the other one is through functions. Think of business lines as mini-companies themselves inside the big company.
Within functions, here are a few most typical divisions most companies have:
Business strategy concepts
Even with business students, strategy is a challenging topic – especially with those without a strategy major. These fundamental concepts will get you started.
For example, let’s look at Kim’s family picnic process.
B2B vs B2C: stand for “business-to-business” and “business-to-customer”. These two terms refer to two types of transactions a company typically does: transactions with other companies and transactions with individual customers.
Bottom-up vs Top-down: this refers to two opposite schools of thought or action. Top-down usually encompasses various general branches while bottom-up tends to narrowly focus.
Management consulting terms & concepts
These are the most common consulting terms you may encounter not just in case interviews but also in consulting tasks.
There are three parameters the consulting world uses in the categorization of businesses.
Normally two consultants ask each other “What do you work on?”, they need to give 3 pieces of information in all of those three parameters, such as “I worked on a Cement project, focusing on Finance, in Southeast Asia”. In fact, all of the McKinsey support networks are organized in this way. During my projects, I would need to speak to some Cement experts, some Finance experts, and some local experts as well.
This chapter is relatively long, yet it is still way shorter than 4 years at business college. I hope this will act as a great prerequisite to your case interview study. Make sure that you have mastered all of these content before really tackling the Case Interview.
Case interview example – The typical flow
In a simplified way, a typical case would go through these phrases (we will talk about exceptions in great detail later):
Case question -> Recap -> Clarification -> Timeout -> Propose issue tree -> Analyze issue tree -> Identify root-causes -> Solutions -> Closing pitch
Let’s say we have a restaurant called “In-and-out Burger” with recently falling profits. How can you help?
Let me playback the case to make sure we are on the same page. So our client is “In-and-out Burger”. The case objective is to solve the profits problem. Do I understand it correctly?
Thank you. The first step in solving any problem is to make sure we solve the right problem. I would like to ask a few clarification questions to make sure I really understand the case from top to bottom. So here are my questions: No. 1… No. 2… No.3 …
*answers without giving away too many hints*
(There are ways to trick him/her to give you more than he/she should. We will talk about this in later chapters below)
(Once felt like the problem is well understood along with a few perks of data, take a timeout to kick start the problem-solving process)
Thank you for all the information. The case objective is very clear now. I would like to take a short timeout to gather my thoughts
Propose Issue Tree
(After an intensive thinking process, you propose an issue tree to break down the problem and hopefully find the root-cause soon. You may also talk a little bit about your overall approach before actually doing it. More on this later!)
To completely solve the problem and create long-lasting impact, we need to dig in and find the real root-causes, not just fixing the symptoms. To do that in the most efficient way, I would create an issue tree and analyze all possible root-causes systematically, in a top-down fashion.
So here is my proposed issue tree for this problem. On the top layer, I would break the analysis into 2 big branches: Revenue and Cost. This overall approach and the issue look ok to you?
Analyze Issue Tree
(Go into each branch, ask for data to test if the branch contains the root-cause. Remember, only test the highest-level branch, don’t go into the sub-branch just yet. More on this later!)
Now I would like to explore the first branch: Revenue. I would like to ask for a few data points to test if the root-cause is in this branch or not. If yes, I would go deeper, creating another layer with sub-branches. If not, I would cross out this whole Revenue branch, and spend valuable time with the Cost branch. Does this issue tree look good to you? [Analyze the tree]
(After the interviewer confirms (mostly likely he/she will), you ask for data to test the Revenue branch. There are many possible tests, but the most simple and popular ones are: historical and competition benchmarks. More on this later.)
Now I would like to explore the first branch: Revenue. I would like to ask for a few data points to test if the root-cause is in this branch or not. If yes, I would go deeper, creating another layer with sub-branches. If not, I would cross out this whole Revenue branch and spend valuable time with the Cost branch.
So, has revenue been increasing or decreasing over the past few years?
(One by one, branch by branch, sub-branch by sub-branch, you analyzed the whole issue and found out rising raw material cost as the key root-cause for the profit problem.)
So we have exhaustively analyzed the whole issue tree and the data clearly shows that raw material negatively affects the bottom line. Fixing this root-cause will completely eradicate the profit problem. The next step is to cure this root-cause.
May I take a time-out to come up with solutions?
(Take time-out to think, and deliver solutions)
Good job finding the root-cause and coming up with those solutions. If you have 30 seconds right NOW to speak with the company’s CEO, what would you tell him?
Mr. CEO, thank you for working with us on this interesting business problem. After rigorous analyses, we have concluded that the rising in raw material cost is causing overall profit to plummet. Here are three solutions: No.1… No.2… No.3…
We’d be extremely happy to continue to work with you to implement those solutions!
Problem-solving fundamentals – Candidate-led cases
Though most cases will be conducted in mixed format, let’s dive deep and learn about each extreme end of the spectrum to get the full picture.
Even though this is the harder format, it shows us the foundation of how management consulting works, i.e: the consulting problem solving logics!
If you were exposed to case interviews, you have probably heard about some of these concepts: framework, issue tree, benchmark, data, root-cause, solutions, etc. But how do they all fit into the picture?
It all starts with the PROBLEM
Before getting into anything fancy, the first step is to define and be really clear about the problem.
This sounds easy but can be quite tricky. Here are a few guidelines:
1. What’s the objective?
2. What’s the timeline required?
3. Any quantified or well-described goals?
For example, one client can state a problem as: “I lost my car key”. In normal contexts, this is a perfectly simple and straight-forward problem. But a consultant tackling this would go ask clarification questions to achieve even more details:
1. Objective: the client in fact just needs to be able to use the car.
2. Timeline: this is an urgent need. He is happy only if we can help him within the next hour.
3. Specificity: help the client put his car into normal operation like before he lost the key.
Find the ROOT-CAUSE, don’t just fix the symptom
To completely wipe out the problem and create long-lasting impacts, consultants always search and find the root-causes.
For example, fixing the symptom is like you breaking the door lock, getting into the ignition electrics behind the wheel, and connecting the wires to start the car.
That does fix the surface symptom: the client can drive the car. But it does NOT create a long-lasting impact because without you there, the car can’t be started. The client will need to rely on you every single time. Plus, more problems even arise (now he needs to fix the broken door lock too).
A much better approach is to find the root-cause. What is the bottom-line reason causing the problem? Once we trace, find, and fix it, the problem will be gone for good.
In this example, the root-cause is “the lost key”. We need to find its location!
Use ISSUE TREE to isolate potential root-causes into groups
There could be thousands of possible root-causes. How do we make sure every possible one is examined? If we are to list out all thousands and test one by one, there is simply not enough time. On the other hand, if we just list out some of the most “possible” ones, we run a high risk of missing the true root-cause.
This is where we need issue trees! We would group possible root-causes into big groups. Those big groups will have smaller sub-groups and so on. All is done in the spirit of top-down and MECE. By doing this, we have an organized way to include all possible root-causes.
Continue with the example: A “bottom-up” approach to search for the car key is to go straight to specific places like the microwave’s top, the black jacket pocket, under the master bed, etc. There can be thousands of these possible locations.
The top-down approach is to draw an issue tree, breaking the whole house into groups and examine the whole group one by one. For example: first floor, second floor, and the basement.
Issue Tree only works if it’s MECE
What happens if we break down the search area into the First floor and East wing? The search area would not cover the whole house and there will be some overlapping which creates inefficiencies.
So for an issue tree to work properly, it has to be MECE – Mutually Exclusive and Collectively Exhaustive … which in simple language just mean 2 things: no overlap and no gap
How to draw MECE issue trees? Use FRAMEWORKS!
Each problem requires an unique issue tree. Coming up with MECE and spot-on issue trees for each problem can be really difficult. This is where “framework” helps.
Think of frameworks as “frequently used templates” to draw issue trees in any particular context. Many people use the word “framework” to refer to “issue tree” but this is conceptually incorrect.
We will talk about frameworks in more detail in the below chapters. You can also check out this deep-dive article on Frameworks.
Choosing which branch to go to first? Use HYPOTHESES!
So let’s say you have an issue tree of First floor, Second floor, and Third floor. Now what?
To make the problem solving process even faster and more efficient, we use hypotheses. In simple language, it’s the educated guess of where the root-cause may lie in. So we can prioritize the branch with the highest chance.
So let’s say, the client spends most time on the first floor, it’s where he/she most likely leaves the car key. Any consultant would hypothesize that the root-cause is in the first-floor branch and go search there first.
Notice: hypothesis and issue tree always go together. It doesn’t make sense to draw an issue of First, Second, and Third floor and hypothesize that the key is in the East wing. Many times, hypotheses are even the inspiration to draw issue trees.
How to test a branch? Use DATA and compare it with BENCHMARK
Now that we decide to test branch “First floor”, how do we do that?
We prove or disprove our hypothesis by collecting DATA. That data is then compared with benchmarks to shed more meaning. Two main types of benchmarks are: historical and competitive. For example, let’s say by some magic, the client has a metal detection machine which can measure the metal concentration of any space.
To test the “first-floor” branch, the consultant would come to the first floor, measure the metal concentration and compare it with the data before the car key is lost, a.k.a: historical benchmark.
If a hypothesis is true, drill down; if it’s false, go sideways
What happens when we test a hypothesis?
Assuming that we have access to enough data, it either gets proven TRUE or proven FALSE. How do we proceed from here?
Test, Sleep, Test, Repeat … until the ROOT-CAUSE shows up!
Once identified the ROOT-CAUSES, go for SOLUTIONS
With all proven root-causes identified, the last step is to come up with solutions to kill the problem … and we are done! There can be multiple solutions to each root-cause. These solutions should attack straight to the root-cause.
Case interview questions – Interviewer-led cases
While candidate-led cases are all about the logical foundation of problem solving, interviewer-led cases are more about tackling each individual question itself. The structure of the whole case is relatively loose and flexible.
In this chapter, we touch on some of the most popular ones. You can read in-depth about each in this designated article.
Framework/Issue Tree questions
This is one of the most popular question types in case interviews, often asked in the beginning. It comes with several shapes and forms, but the real meaning is always: “Give me the bloody issue tree!”
So how do you tackle it? Just like in candidate-led cases. Take a timeout; brainstorm about the problem and how it should be broken down into; plug a few frameworks to see how it looks; and go for the most appropriate issue tree.
Unlike in candidate-led cases where you only present the upper-most layer, here you should walk the interviewer through the whole issue-tree, covering at least 2 layers. Interviewer-led cases are much less interactive. It’s more like they ask you a question, you deliver a comprehensive and big answer. They ask you another one. And so on.
Market-sizing / Guesstimate questions
This is among the most popular question types and you will likely face a few of them throughout several interview rounds. These questions ask you to “guess” and come up with number estimations in non-conventional contexts. These questions are called “Guesstimate”.
When a guesstimate question asks you to “guess” the size of a market, it’s called a “Market-sizing” question. Though this variation is very popular in consulting, the nature is nothing different from other Guesstimate questions.
It can be intimidating to face a question like this. Where to start? Where to go? What clues to hold on to?
The key is to understand that you don’t have to provide an exactly correct answer. In fact, nobody knows or even cares. What matters is HOW you get there. Can you show off consulting traits, using a sound approach to come up with the best “estimate” possible?
Read the designated article on this for great details. Here, let’s walk through the 4-step approach that you can apply to absolutely every market-sizing question.
how much money will they save on production cost?”
Almost all cases involve some math. So you will face math questions for sure. These “questions” can go at you either explicitly and implicitly. Sometimes, the case interviewer will ask out loud a math problem and have you solve. But sometimes, you have to do multiple calculations on the background to push the analysis forward.
Either way, a strong math capability will help you a lot during cases and the future career in consulting. See this Consulting Math article for more details.
Chart insight questions
Consultant works with data and a big chunk of those data are presented by charts. Many times, the interviewer would pull out a sanitized exhibit from an actual project and have you list out insights you can see from it.
There are many types of charts. Getting yourselves familiar with the most popular ones is not a bad idea.
Tips on tackling chart-insights questions:
1. Read labels first: from Chart titles, Axis title, Legend title, etc. Don’t jump straight to the content of the chart. It takes more time to get lost there and having to go back to read the label. Besides, you may also run a risk of mis-understanding the content.
2. Look for abnormalities: important insights always lie in those unexpected and abnormal data. Look for them!
Value proposition questions
when deciding which car insurance company to buy from?”
In simple language, this question type asks you: what do the customers want? Understanding exactly this need will put any company into the best position to tailor products / service.
Like any other questions, Value-proposition questions are not only about correctly identifying customer preferences (insights), but also about analyzing and delivering the answer in a structured fashion. Here are a few tips for you to do that:
How to be more insightful:
How to appear more structured:
What kind of data do you need to test this hypothesis? How do you get data?
Consulting is a data-driven industry. As consultants, we spent most of our time gathering and presenting data to clients ( see the What the heck does a consultant do video). No surprise information questions are relatively popular in cases.
The best way to tackle this question type is to understand inside out the types of data actual consultants use in real projects. Because almost no candidate knows about this. This is also a very quick way to build rapport. The interviewer will feel like he/she is talking to a real consultant.
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Case interview example video – Pandora case
Enough theory! Enough cute little illustration here and there. Time to get our hands into a serious case interview example.
Notice the following when watching the video:
Every case is unique in its own way but principles are universal. The more examples you see, the better. This video is extracted from our Case Interview End-to-end Secrets program, where you can find 10 complete examples like this and many other supplement contents.
How to prepare for case interviews
Case Interview preparation is a long and tough process. In an ocean of books, videos, programs, how do we navigate to maximize learning? Most materials floating around are quite good, at least in terms of substance. But the timing and the organization of them can be confusing.
So a good study plan is constantly switching between 3 activities: reading theory, watching examples, and practicing, with cases increasing difficulty level. It’s so crucial to start with super easy cases, be patient, and stay on that level until you are ready to move up. There are so many skills, habits, and scripts to develop and these take time.
“The quickest way to do just about everything is … Step by Step”
Even for candidates with cases coming up urgently, I still strongly recommend spending the most valuable time practicing cases that match your level. After all, cases are just the context. What you will be evaluated on is your approach, your skills, your techniques, etc.
So, this is a sample study plan you can adopt for yourselves:
• Read this article thus far
• Watch this Case Interview 101 video
• Read the sample case flow above.
• Watch this Case Interview Example video
• Go to this list of free case examples and try to select a very simple one. If you can’t follow one, it’s probably not good for you. Just skip it.
• Watch the first example in the End-to-end Program
• Watch intensively about the logical foundation of problem solving in this Candidate-led cases video.
• Practice with consultants. They have the insight and knowledge to help you pass the interview. Discover our experienced coaches from McKinsey, BCG and Bain here.
• Find a partner to practice with. Make sure you both watch this Guide on how to conduct a case. A bad coach can do more harm than good.
• Get your hand on another example in the End-to-end Program. But this time, don’t just watch. Actively solve the case as you see it! Try to say out loud your version, then listen to the candidate, then hear the feedback!
You can do this by:
• Read consulting publications. One article per day for example. Three wonderful sources are: McKinsey Insights, BCG Perspectives, and Bain Publications
• Train case interview questions individually. By isolating each part of the case, you can focus more on the substance. Hit that link or get more question training on the End-to-end Secret Program.
• Visit this in-depth consulting math article.
• Train our Mental Math methodology.
• Book a meeting with coaches
• Find another partner to practice with. Just make sure you both watch this Guide on how to conduct a case. A bad coach is always more harmful than not practicing at all.
• See another example in the End-to-end Program. Like the previous one, try actively solving the case as you see it! Say out loud your version, then listen to the candidate, then hear the feedback!
• Read on! The below chapters of this very article will provide you with more advanced theory and killer tips.
• Watch the whole Tips & Techniques sections of the End-to-end Program. You will find 10 examples with clear walkthroughs of tips and techniques right in the middle of real action.
• First, brush up on knowledge related to case interviews with the Case Interview End-to-End Secrets Program.
• Second, get personalized practice with ex-consultants. That way, you’ll receive clear and tuned feedback to understand what to improve, building your own proper case approaches. See a list of experienced coaches here.
Stay tune with us on this website and our Youtube channel for continuously updated information on case interviews and management consulting recruitment; you can also subscribe in the newsletter below for free materials and other insightful contents!
Good luck with your case prep!
Case interview tips – With instant results
Imagine a case interview just falls out of the sky and into your lap, scheduled for tomorrow – how can you even prepare?
The answer lies in a few “quick and dirty” tips, which I’ll share with you in a moment.
I am a firm believer in the 80-20 rule – which states that 20% of the causes lead to 80% of the consequences.
In the case interview prep context, 20% of your learning efforts will bring about 80% of the improvements – so the key to instantly and dramatically improve your case performance is to identify and focus on that 20%.
In the next 8 chapters, I’ll tell you the killer tips and tricks that helped me get a McKinsey offer, the majority of which were previously only available in the premium End-to-End Secrets Program, including:
One thing before you proceed: don’t forget to learn the fundamentals, the question types, and the frameworks. Remember, these 20% tips can only get you 80% performance; if you want 100%, there’s no substitute for hard work.
End-to-End Secrets Program
10 case interview Tips & Techniques videos
+1,400 Consulting Math questions
60+ Business Intuition exercises
PEI & Fit Interview deep-dive guide
How to deliver the perfect case opening
The result of a case interview is determined the first 3 minutes – and I’m not even exaggerating.
Most people will be put off by this fact – indeed, with all those efforts spent on learning for the later part of the case, and the hiring decision is made when you’re not even properly warmed up yet.
However, putting a spin on it, this is the 20% to focus on – if you nail the opening, you’ll make a better impression than most candidates; it’s also easier to perform well in 3 minutes than in 30 minutes, especially when the case hasn’t gotten tricky. Additionally, you can prepare the opening in a formulaic manner – essentially learning by heart until it becomes natural.
There are 7 steps in the perfect case opening formula:
1. Show appreciation
2. Announce case introduction
5. Announce case approach
7. Ask for timeout
In this chapter I’ll walk you through each of those steps.
Case interviewers are not dedicated HR staff, but Engagement Managers, Partners, and Directors who conduct interviews ON TOP OF their projects as goodwill for the firm, so you should at least be thankful for the time they spend with you.
Begin your interview with a sincere “thank you” for the interesting case (if you have to fake these words because deep down you don’t like case interviews, you aren’t exactly cut out for the job).
This step is related to what I call the “map habit”, which I’ll describe in detail in the next chapter. For now, just understand that it helps the interviewer follow your introduction, and shows you’re a structured person.
On a side note: one common mistake is to mix up step 3 with step 4 (clarify) – remember, don’t ask anything, just rephrase the case to ensure that you get it right.
Case questions are always very short with a lot of vague details; if you don’t see the need to ask anything, you’re doing it wrong.
Run this checklist through your mind to help you clarify as many unclear points as possible:
• Definitions: are there words you don’t understand, or can be interpreted in multiple ways?
• Timeframe: what is the “deadline” for solving this problem?
• Measurement: how are the important variables (performance, revenue, etc.) measured?
Additionally, number your questions so it’s easier for you and the interviewer to keep track.
Again, this is related to the map habit, which makes the overall case progress easier to follow.
There are 3 types of cases: (1) problem-solution, (2) should I choose A or B, and (3) how to do C. For each type there is a different approach. The latter two are discussed in the “Advanced Logic” chapter, for now we’ll continue with the first type: tell the interviewer you’re going to find the root cause to ensure long-lasting solutions, and to do that you’ll develop an issue tree.
This is an important habit of real consultants, because nobody wants to waste resources going in the wrong direction; interviewers expect candidates to show it in the case interview.
Simply ask “Does this sound like a reasonable approach to you?” – most likely the interviewer will give you the green light, but if you’re lucky he/she may even suggest a better approach.
Make the most of your timeout session, and keep it as short as possible. Any unnecessary silence will damage the impression and hurt your chances (refer to the End-to-End Program example in Chapter 6 to “feel” how awkward a lengthy timeout session is).
Case opening – Example script
Now it’s time to see how you can put all those steps into action!
The first step in solving any business problem is to make sure we solve the right one, so before diving into the problem, I would like to first recap the case, then ask a few clarification questions to make sure we’re both on the same page, and lastly announce my overall case approach.
So here is my understanding of the case:
Does that correctly summarize the case?
<assume the interview confirms that your playback is correct>
Great, now I’d like to ask my three clarification questions:
<wait for answers>
Thank you for the clarification. Is there anything else I should be aware of?
<wait for answers>
Thanks for all the insights. It’s great that we all agree on the key details.
For the overall approach to this case, to completely wipe out the problem for a long-lasting impact, we will need to find out the root causes of this problem. To do that I will try to break the problem down into bite-size pieces with issue trees, in order to quickly isolate the root causes inside the branches, then drill down accordingly to gather information until we can draw actionable solutions.
So before I go on to establish my first issue tree, does that approach sound reasonable to you?
<assumes the interviewer agrees with your approach>
It’s great to see that we’re on the same page regarding the key details as well as the overall approach to the case. I do need some time to gather my thoughts, so may I have a short timeout?
Being structured throughout the case
The high stress and large amount of information in case interviews make it easy for even the brightest candidates to derail from the objective or present in an unstructured manner.
I’ll be sharing with you my 3 most impactful tips to keeping the structure in case interview:
1. The map habit
2. Numbering your items
3. Sticking to the big problem
The map habit
It means regularly and explicitly checking where you are, and where you’re doing next.
I call it the map habit because it’s similar to using a map while traveling – pausing every once in a while to check your location, destination, and direction.
This habit gives you a sense of direction and authority while making it easier for the interviewer to follow your case progress. It also makes you sound organized and systematic – a definitive mark of management consultants – and the interviewer will love it!
You’ll see this habit a lot in our Case Interview End-to-End Secrets Program, where candidates would often pause at each key step during the case. Do the same thing in your own case interviews, and you’ll greatly impress the interviewer.
Numbering your items
A very easy and effective way to make your pitches sound structured is to number each item.
The formula is simple: “There are X items that I’m going to say; they are: No.1 … No.2 … No.3 …”
By now you may have noticed that I use this structure many times throughout this guidebook – it’s already quite effective in written language, but it’s even more impactful in spoken communications!
Having this numbering habit will make it very easy for the listener to follow your speech, and it creates an impression of MECE (even if content-wise it’s not MECE).
Sticking to the big problem
There are two ways to keep yourself on-track all the time in those high-stress case interviews
1. Occasionally check your position on the issue tree, and quickly get back on track if it seems you’re “derailing”. If this sounds like the previous map habit, you’re right, it is the map habit.
2. Take good notes, with the case question being written big and bold on top of your scratch paper. That way you’ll be reminded every few seconds.
That last point brings us to the next issue: how to take notes.
How to take notes in case interviews
The best notes for case interviews are always clear-cut, structured, and relevant.
Even the smartest candidates suffer from seemingly silly problems in case interviews – forgetting data, messing up the numbers, getting stuck with frameworks, losing sight of the original objective, etc. And in the true management consulting spirit, I set out to find the root causes.
And looking back at hundreds of coaching sessions I did, I found one thing in common – none of those candidates could take good notes.
I’ll tell you precisely how I took notes to get a McKinsey offer; however, I hope that after this chapter, you can install the spirit of the method, not just the method itself.
So here we are, with the 3 groups of sheets laid out for the ideal note-taking:
1. Data sheets
2. Presentation sheets
3. Scratch sheets
Data sheets are used to store and process every piece of incoming data.
Try to draw tables for these sheets, because this not only makes the calculation process easier, but also gives the impression that you’re a careful and organized person.
Also, remember to write only the results of calculations on this sheet, to keep it neat and tidy. Most of your calculations should be done mentally (see the article on Consulting MathConsulting Math for more details); if you really need to jot down the calculations, do it on the scratch sheets.
Presentation sheets are used to develop and present any “outgoing” contents.
Your issue trees should be drawn on these sheets, along with the big-and-bold case question/objective right on top. When delivering your pitches, always turn around the presentation sheets so the interviewer can clearly read what’s on them.
As with the data sheets, avoid any messy “mid-process” drawings. Put them on the scratch sheets instead.
Scratch sheets exist to keep other sheets clean.
Ever felt irritated receiving a notebook full of correction marks? That’s exactly how the interviewer feels if you present with untidy notes. You should try your best to hide all the unorganized, messy parts of your thought process.
The scratch sheets provide a sanctuary for that unstructured part of yours – it’s okay to go all over the place for brainstorming, as long as you can organize the incoming resources and present in a systematic manner.
“I took the notes just as you instructed, but I still get stuck in cases. How can I avoid it?” – Well, that’s the subject for our next chapter – “Stuck” situations and how to get out of them.
Stuck in cases – What to do
We’ve all been there – that scarily awkward feeling when you don’t know what to do next in a case interview, that fear of being rejected.
In every “stuck” situation, the most important thing is to remain calm and collected (you’ll lose points if you panic) – then methodically work your way out. I’ll teach you how to get out of those situations, with style.
There are actually 3 different kinds of “stuck”, and for each, I have a different solution:
1. The “Framework” stuck
2. The “Data” stuck
3. The “I-Cannot-Find-The-Problem” stuck
Let’s go through each in detail.
The framework stuck
This situation happens when the candidate does not know which framework to use, and the secret tool for it, is “segmentation”.
Segmentation works just like any framework, and like a Swiss Army knife, it’s usually safe and easy to use. So if you’re unsure how to break things down, say these magic words:
“At this point, I’d like to break down this X item, and one good way is to use the natural segmentation within this line of business. So may I ask how they break this X item in this industry?”
If you get it right, the interviewer will reply with the most industry-relevant way to segment the item.
You may be wondering why I’m not talking about issue trees and frameworks here, after all the theory at the beginning of the guidebook.
The answer is that the textbook and “ideal” solution – learning the problem-solving fundamentals and deep-diving the frameworks to increase your flexibility – takes a lot of time, while the “cliched” solution – learning as many frameworks as possible, usually at the cost of depth – is inherently dangerous.
The data stuck
The “data stuck” happens when the candidate can’t extract relevant insights from the given data. And when this happens, ask for benchmarks.
Comparing with benchmarks is the quickest way to put data into perspective, yielding useful insights. There are 2 kinds of benchmarks – if you remember from the chapter on Candidate-led Cases:
To ask for benchmarks, Just say the following lines:
“For now, I hypothesize that the root cause of the problem comes from the X branch of this issue tree. However, to further break down the problem in a spot-on way, I do need some information on the context of our client’s problem.
One of the quickest ways to grasp that context is to use competitor’s data; so can I have the X figure for our client’s competitors?”
The “I-Cannot-Find-The-Problem” stuck
This is the scariest “stuck” because there’s no obvious reason or solution – you’ve done your math right, your framework is suitable, and you’ve got a lot of interesting insights from data. Why are you still stuck?
From my experience in coaching sessions, there are 2 scenarios where this happens: (1) your issue tree is not MECE, and (2) if your issue tree is MECE, it does not isolate the problem.
You can try to avoid this in the first place by mastering the MECE principle, improving intuition, as well as aligning with the interviewer early and often.
But what if you still get stuck? The answer is to calmly admit you’ve hit a dead-end, and ask for time to fix the problem; be it the first or second scenario, you have to redraw your issue tree.
Literally use the following script:
“My whole analysis seems going towards a dead-end, which means either part of my issue tree is not MECE or my method of breaking down does not isolate the problem. Either way, I would like to take a timeout to have a look at it.”
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How to ask for data
Data is the fuel for the case interview engine. Without it , your analysis can’t progress.
The problem is that interviewers don’t simply give out precious data for free. It has to be earned. There are 4 tips you can use to show that “worthiness”, and prompt the interviewer to supply you with the best information:
1. Create a good impression
2. Explain the purpose of the data
3. Explain the method of acquiring the data
4. Ask open-ended questions
In this guidebook, there are countless tips to show your consulting characteristics – I even write a whole chapter on how to install consulting culture into your own personality. Generally, you must always be (1) structured, (2) fact-based, and (3) action-oriented.
Additionally, common people skills and interview tips also apply – show your appreciation by thanking for their help, keep a smile on your face to maintain a positive atmosphere, etc.
There are only two purposes for data in case interviews: (1) to test a hypothesis, and (2) to understand the context.
You can use the following scripts to when to reason your data requests:
“For now, I’m hypothesizing that the root cause of this problem comes from the X branch. Since this hypothesis can only be tested with the data on X, may I have those figures?”<
“For now, I hypothesize that the root cause of the problem comes from the X branch of this issue tree. However, to further break down the problem in a spot-on way, to better understand the context of our client’s problem, I will ask a few more questions. Does that sound reasonable to you?” <
In real consulting projects, data is not always available; the interviewer may rely on this logic and refuse to give you any information. So, when you ask for data, make sure your request is realistic, then state the method to acquire it using these words:
“If this was a real project, this information can be acquired from/by X source/method”.
In our Prospective Candidate Starter Pack, there is a sheet listing all the possible sources of information in consulting projects, which you can download for your own use, along with many other free case interview materials.
Accurately explaining the data acquisition method also shows that you’ve done your homework and you know the consulting industry inside-out. Any interviewer will be greatly impressed.
The precise questions mostly depend on specific cases (meaning you need to sharpen your intuition), but there is a Swiss Army knife here: “Is there anything else?” – which is a question real consultants ask several times a day, at the end of their conversations.
Use open-ended questions when you feel you might be missing something – for example, during clarification – and only after a series of well-defined, close-ended questions. Otherwise, you risk appearing lazy and over-reliant.
What to do when receiving data
Suppose the interviewer agrees to give you data. Now what?
Time to shine! If you do these following 3 steps, even just once, in the interviewer’s mind, you already pass:
1. Acknowledge the data and show appreciation
2. Describe the data, especially its notable features
3. State the implications of the data
Let’s dive into each separately.
Firstly, it confirms that you have received, and can understand the data.
Secondly, it’s always good to give out modest, subtle compliments to the interviewer. Trust me, conducting case interviews is hard work, and the interviewer does appreciate those little compliments.
Last but not least, it buys you a few seconds to fully absorb the new information and minimize any possible silence.
Don’t recite a short essay about the data, there is no time for that. Quickly and mentally calculate all the important points, then state it out loud in 1-2 sentences.
This step has several uses:
It showcases your consulting math skills (chart insights and mental calculation)
It eliminates the silence during your analysis
It helps you quickly memorize the key trends in the data
This part is extremely important because it connects to the action-oriented mindset of actual management consultants, while laying solid foundations for your next steps (fact-based).
Example – Handling revenue data
Suppose you’re working on a profitability case (how to fix low profits), and you’re trying to dictate whether the root cause comes from the revenue side.
The interviewer gives you this data:
How would you respond? Try to answer it yourself before revealing the sample answer.
Thank you for the very interesting data. (acknowledging)
It seems that our client’s revenue has been increasing steadily throughout four years – around the mark of 20% annual growth, in fact. (describe the data)
This suggests that the problem may not come from this side of the issue tree. However, in order to fully reject the possibility, I need the figures on the revenue of other companies in this industry around this time. Do we have those numbers? (implications)
Delivering the perfect closing pitch
“You have one minute to summarize all of your findings to the client CEO. What would you say?”
Your answer must be short, to-the-point, action-oriented, and client-friendly.
The closing pitch of the case interview is sometimes called the “elevator pitch”, where you supposedly meet the client CEO inside the elevator and must somehow deliver the results of the project before the elevator arrives at its destination floor (it’s even worded like that sometimes).
Regardless of the wording, the principles remain the same, and your closing pitch must consist of these 4 parts:
1. Introduction / Lead-in
2. Summary of the root causes
3. Summary of the solutions
4. Next step
There is a simple formula for this part of the pitch:
“Mr. CEO, it has been a great pleasure to be working with you on your company’s X problem.”
Everybody loves a little compliment, don’t they?
CEOs are busy people, they have no time for a 15 minutes break-down of your issue tree. They only care about the “big picture” – “why is the problem happening?”.
You need to sum up root causes in a structured manner, with a numbered list – in the case interview context, that’s one characteristic the interviewer looks for, and in real projects, it helps the listener follow your pitch.
“After careful analysis, we have found X root causes for the company’s problem: 1… 2… 3… X”.
This step must also be structured. Additionally, list the solution in the same order as their corresponding root causes, to imply the connection between them (if the root causes are listed as A, B, C, then the solutions should never be C, B, A).
“To solve the aforementioned issues, we propose the X following solutions: 1… 2… 3… X”.
This step shows that you have an action-oriented mindset and necessary people skills to represent the firm before the clients.
Moreover, follow-up implementation projects are a major source of revenue for the top consulting firms (such as McKinsey, BCG or Bain), so mentioning them in your case interview ending pitch proves that you did the appropriate research before applying.
So here’s what you’ll say when the elevator reaches the destination:
“We would be more than happy to work with you to implement these solutions”.
Develop personal interview scripts
Every tip I’ve mentioned in the previous 7 chapters are for recurring situations in case interviews, and they can be dealt with using formulaic responses.
What that means for you – the candidate – is that you can make personal scripts and learn them by heart until they all become your second nature. That will save you a lot of brainpower to use on the issue tree. This approach has proven successful with all of my coachees, and it’s also a major part of our Case Interview End-to-End Secrets Program. You will find my own personal script I used back in the day, and I will also personally give feedback to scripts of members of the program.
So open your document tool and start writing now. Once you’ve finished the scripts, learn them by heart one at a time. When you feel comfortable with every one of them, you can move up to a higher level and practice with whole cases.
Inside the case interviewer’s mind – Consulting culture
The best way to impress your consulting interviewer is to act like a consultant. And to do that, you need to know what goes on inside their mind – both the conscious and unconscious – then install it into your own personality.
In this chapter, I’ll guide you through 15 ingredients that make up a consulting mind. However, I won’t tell you how to apply this in case interviews because it will sound fake – what you need is to immerse yourself in a consulting environment, and incorporate these “ingredients” into your own mindset.
Responsibility & proactivity
Everyone talks about responsibility and proactivity these days, but in management consulting, we have a much more powerful word – “ownership”. When you “own” the work, you deeply and sincerely care about it, and you always try to go beyond what is required.
If you ever spend your efforts trying to improve a piece of work that your boss already approved, just because you know it is the right thing to do, because you feel so good seeing a job well-done, you have that “ownership” mindset.
In management consulting, you are expected to possess that mindset. In my early days at McKinsey, I was almost thrown out the window for working on a cement project but not knowing where the aggregate mines were (which was outside my responsibilities, but my boss expected me to know it, since I “owned” that cement project).
If you fail to do your work, don’t ever blame anyone or anything. Your responsibility is to draw up contingency plans for the “worst-case scenarios”:
In short, if you want to be a consultant, don’t make excuses.
Result-oriented / Can-do attitude
“There’s nothing I can’t do” – that’s the mindset you need to work in management consulting.
The result orientation inside a consulting firm is intense – saying that it’s “Mission Impossible” everyday would not be an exaggeration, but at the end of the day it’s always “Mission Accomplished”.
The boss doesn’t pay much attention to how you do a task, or what resources it takes, as long as you get it done. The firm has enough resources of every kind to help you with that, so there’s no reason you can’t pull it off.
Communications made by consultants are always short, concise, to-the-point, action-oriented, and structured.
We were all given full-on lectures by our parents back when we were kids, for wasting food or not exercising (or not studying, for Asians like me). If they were management consultants, most of those lectures would be replaced with powerful, action-oriented messages: “Go study. If you don’t get an A+ for the next test, I’ll have to discipline you”.
A consultant seeing something non-MECE is like your mom seeing your messy bedroom. It’s that discomforting.
If you wish to be a consultant, train yourself to be MECE in everything you do. Once you can be MECE effortlessly, and you start spotting the annoying non-MECE-ness in everything around you, you know you’ve got it.
If you’re unstructured, you won’t get in the business.
Being “structured” is a pretty vague concept, but everyone in the consulting industry knows when they see it. It’s about being organized, logical, top-down, MECE, etc.. Basically, if you can approach things the same way as real consultants, you will be deemed “structured”
If you can’t meet the deadline, you’re dead (of course, not literally).
A consulting firm works like the perfect machine, where every part operates as intended. When consultants promise to help you with something, you can be nearly 100% sure that they’ll keep their word. This makes work management that much easier.
Consequently, if you start missing the deadlines, you’ll be out of the game soon enough.
Manager from Day 1
You’ll get the idea right away if you watched this video on the job of management consultants:
In short, even as an entry-level associate, you’ll be managing a multitude of resources (experts, specialists, etc.), contents (reports, client data, expert knowledge,…), and stakeholders (the two most important being your client and your boss).
Pulling all of these together to create impactful results would be an impressive feat, even for the best and brightest new hires.
Don’t. Ever. Piss off. The client.
Management consulting is a special service industry – besides the usual “don’t disrespect the client” and “don’t leave a bad image of the firm”, there’s also “don’t make them hate you while telling them to do what they probably hate.” (which is a good way so sum up a consultant’s job).
In case interviews and PEIs, the interviewer will be asking himself a big question: “Can I trust this guy to represent me and my firm before the client?” – if the answer is anything below a stellar impression, you won’t be receiving an offer.
A consultant will have valid reasons for everything they do.
In both consulting work and case interviews, you need to be very explicit about the basis of your actions – every conclusion must have backing data, every idea must be explained, and every request must serve a purpose. Don’t ever assume that you’re justified.
Being fact-based is part of the foundation for the trust people place on consulting firms, so people who draw ideas out of thin air and act impulsively will never get into the industry.
Effective time & resources management
Every consultant works hard, so the only way to stand out is to work smart.
Yes, I know it’s a buzzword, and I know it’s cliched, but the 80-20 rule really does apply in this line of work. The best performers are always the ones to identify the most important lever and focus on it.
With the intense workload and up-or-out policy at major consulting firms, this skill is vital. Don’t be surprised if you pull all-nighters and work hard all the time but still get fired, while that one guy who goes home at 5 gets promoted. If you want to survive, learn from him.
Key take-aways & key messages
To a management consultant, everything has a key takeaway.
Consultants are efficient people, they don’t simply waste time, effort, and resources on irrelevant things. Things are only worthy of their attention if they have an interesting, helpful “so what”:
If you already think like this, trust me, the interviewer will love you.
Think on your feet first
You should only ask leadership assistance only after you’ve thought well about the problem.
Just pause for a second and think: would you be more ready to help someone who really tries their best at the job, or someone who does nothing and relies solely on you?
The same thing is true in consulting work, and even in case interviews: the interviewer will assist you if you can deliver well-informed opinions.
With that said, “asking without thinking first” is a very common mistake in case interviews, which you can see in the numerous examples from our End-to-End Secrets Program.
Align early, align often
Always try to reach and maintain a consensus with co-workers and your boss, from the most mundane tasks to the largest projects.
Nobody wants to spend a whole week building a model that the team doesn’t need; it’s a huge waste of time and resources. As such, consultants have this aligning habit very early and often – a little time spent on reaching an agreement now will save a lot of trouble later.
Remember to align in case interviews as well – at the start of the case, and every important step.
Consultants are very action-oriented people who always think about the next step.
Every meeting, phone call, even random catch-ups must end with everybody being explicitly and absolutely clear about what to do next.
So what’s YOUR next step, after reading this guidebook?
Leave a comment below, show your consulting mindset, and I’ll personally reply with advice on your case interview prep.
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