Case Interview Prep Guide (5 steps to an offer at MBB)

By Max Serrano with input from the following coaches: Kai H , John E , Adrian C , and Garvit B . March 18, 2024

A case interview candidate looks at her two interviewers

Case interviews at the top consulting firms aren't as difficult as they seem, but in order to pass, you will need to prepare extremely thoroughly. In this article, we show you how.

We've helped thousands of candidates ace their management consulting interviews and get jobs at Mckinsey, BCG, Bain, and other top firms. Below we've summarised the five main preparation steps you'll need to take to succeed in your case interviews.

And here's one of the first things you'll want to know:

Memorising pre-made frameworks will NOT impress your interviewers. You need to learn to create custom frameworks that are tailored to the details of each individual case. We'll cover this in more detail in section 2 below.

Here's an overview of your five preparation steps (click to jump to that section):

Learn what to expect in a management consulting case interview
Get a succinct overview of what case inteviews are, how they work and the differences between top consulting firms.
Learn a structured approach to case problems
Understand how to solve cases in a methodical and structured manner.
Solve practice cases (33 free example cases)
Find links to example cases from the top firms. Working through cases is a key part of your prep
Improve your case interview technique
Read tips from our experts on how to perform better in case interviews.
Practice, practice, practice
First practice on your own, out loud. After that, doing mock interviews with anyone will improve your chances, but doing mocks with ex-consultants is a game-changer.

You can use this guide as a launchpad for all your case interview prep. When you need to go deeper into a sub-topic (such as using frameworks, case examples, specific firms, even what to wear, etc.), just click on the relevant link.

Click here to practise with MBB ex-interviewers

How we wrote this article

This article was originally written by two ex-consultants, Max and Jon. We also talked to six expert consultants from top firms: Bain, Oliver Wyman, EY, and Accenture. Our particular thanks to John, Garvit, Adrian, and Kai for their input.

We update this article a couple of times a year to make sure it's up-to-date with current case interview practices.

Step 1. Learn what to expect in a consulting case interview↑

1.1 What is a case interview?

Case interviews (sometimes called case study interviews) are used by consulting firms to test candidates on their problem-solving, maths, communication, and business sense skills. They usually last ~1 hour and they are the core of the consulting interview process.

1.2 What is the format of a case interview?

In a case interview, you are presented with a case study about an imaginary company facing a problem or challenge. You'll need to review the information, ask questions to get more information, and then provide recommendations on what actions the company should take.

Most case interviews are made up of the following six components:

Case prompt
Framework development
Framework exploration
Quantitative question (with or without data)
Brainstorming
Recommendation

Depending on what firm you're interviewing for, the interviewer may control the case interview by asking you a list of questions, or you may be expected to take the initiative in the discussion.

Some firms, such as Bain and BCG, also use case presentations. In these, you are given a couple of hours to analyse a pack of documents and create a presentation (you can learn how to prepare for that in our guide to written case interviews).

1.3 Why do consulting firms use case interviews?

Case interviews aim to simulate, as accurately as possible, the day-to-day of a management consultant. If a candidate does well, the interviewer can be fairly confident that they've got what it takes to succeed in the role.

"To make it as realistic as possible, interviewers often use questions from actual situations they've experienced with clients. So case interviews help consulting firms understand if the candidate is someone they can put in front of their client and is fit to represent the brand that the company carries." Garvit (case interview coach, former manager at EY)

Let's take another look at those six components of case interviews. Garvit explained to us that at each stage, you're being tested on a different set of skills as you work your way toward satisfactorily solving the problem.

Case prompt: tests your ability to filter information and focus on a relevant topic
Framework development: tests your problem-solving skills
Framework exploration: tests your problem-solving skills
Quantitative question: tests your quantitative and analytical ability
Brainstorming: tests your creative thinking skills
Recommendation: tests your business sense

1.4 Are case interviews the same across all consulting firms?

There are generally two styles of case interviews used across all main consulting firms: candidate-led and interviewer-led.

Candidate-led (used by Bain, BCG, Oliver Wyman, and almost all other firms): In this format, interviewers give you more control over the pace of the interview. You're expected to take the initiative and lead the way to solving the problem.

Interviewer-led (used by McKinsey): In this format, interviewers tend to control the pace of the interview much more. They will have a list of questions about the case they want to go through with you, and will take you from one question to the next. If they feel you spend too much time on one question, they might interrupt you and ask the next question.

Some consultants say that candidate-led interviews are harder because you have to take charge. Adrian (case interview coach and ex-BCG interviewer), gave four reasons why candidate-led interviews are harder:

There's more to think about: you're responsible for not only solving the case but also for guiding the discussion, asking the right questions, and managing the flow of information.
You have to identify what's important without much guidance.
You have to decide on the direction of your analysis with minimal cues, so you'll need good business intuition.
It's up to you to keep the conversation focused on relevant areas.

Another difference between firms is that Bain tends to use a lot more charts in its case interviews compared to McKinsey, BCG, and others. John (case interview coach and ex-Bain interviewer) told us that "at Bain, you could easily see three to six charts in one case, or even more."

For more information on interviews at specific firms, see our bespoke interview guides:

1.5 What's the difference between first- and second-round case interviews?

Kai (case coach and ex-interviewer at EY and Accenture) explained that there are, in fact, significant differences between first- and second-round case interviews:

Structure: Second-round interviews can often be more unstructured, without any graphs or exhibits, more focused on the brainstorming and creativity part, and on testing your business judgment.
Complexity: Second-round case interviews may involve more complex cases or scenarios compared to the first round. This is because candidates have already demonstrated basic problem-solving abilities in the initial round.
Depth of analysis: Second-round interviews may require candidates to delve deeper into their analysis and recommendations, exploring various aspects of the problem in greater detail.
Behavioural questions: While first-round interviews often focus solely on case studies, second-round interviews may include a behavioural component, such as discussing past experiences or fit with the company culture.

There is also a difference regarding who will be interviewing you. You can expect a first-round case interview to be run by an Associate (2+ years of experience) or an Engagement Manager (4+ years of experience). In contrast, in the second round, you'll be interviewed by Partners (+10 years of experience) who are more likely to ask you tougher questions.

In theory, the firm takes into account your performance at both first- and second-round interviews when making final offer decisions. However, in practice, your performance during the second round carries more weight.

This is simply because Partners will have a stronger voice when the recruiting group discusses your application. It is therefore particularly important that you do well at your second-round interviews.

a huge sumo wrestler, the partner, stares down at a tiny man, the consultant

1.6 What are the different types of case interview problems?

Case interview problems used at the top consulting firms are generally one of the following:

Profitability Cases: These are the most common type of consulting interview cases. They focus on identifying why a company's profits are declining or stagnant. Candidates need to analyze costs and revenues to pinpoint issues, such as rising expenses, falling sales, or market changes, and then recommend strategies to improve profitability.
Market Entry Cases: These cases involve deciding whether a company should enter a new market. This includes evaluating market attractiveness, competitive landscape, and the company's ability to succeed in that market. Market sizing often plays a key role here, as candidates need to estimate the potential market size and revenue opportunities.
Merger & Acquisition (M&A) Cases: In M&A cases, candidates assess the potential value and risks of a company acquiring or merging with another business. This includes analyzing the strategic fit, financial benefits, cultural alignment, and potential synergies or integration challenges.
Response to Competitive Threat Cases: These cases focus on how a company should respond to a new or existing competitor threatening its market position. Candidates need to evaluate the competitive landscape, assess the company's strengths and weaknesses, and recommend strategies to counter the threat, such as changing pricing, improving products, or entering new markets.
Pricing Cases: Pricing cases revolve around determining the optimal price for a product or service. Candidates must consider factors like cost structure, customer demand, competitor pricing, and the overall market strategy. The goal is to find a price point that maximizes profits while maintaining competitiveness.

Click here to learn about some other common types of case interviews.

Step 2. Learn a structured approach to solving cases↑

Whichever type of case you're given, you can follow this structured approach.

Ask clarification questions
Create a case framework
Explore the framework
Do the maths
Brainstorm
Make a recommendation

Let's dive into each step:

1. Ask clarification questions

As the interviewer lays out the case problem, you need to snap into full concentration mode. You'll need to write down all the key points from the information they give you, and once you've got it down, summarize the problem back to the interviewer.

This has two benefits: it's a great way to make sure you've properly understood the most important details, and it gives you some thinking space to think of clarification questions.

There will ALWAYS be clarification or follow-up questions worth asking. For example, imagine you've been given a case where you need to help a client turn around declining profits. You could ask:

How much have profits been declining?
When did the decline begin?
What is the nature of the decline? Have they been declining at 1% per year for the past 5 years, or is it a recent and sudden 20% drop?
What’s the CEO’s objective? For example, are they aiming to just stop the profit decline or do they want to reverse the trend?

When the interviewer has answered your follow-up questions and you've written down the additional information, ask for a minute to create a framework.

Case prompt and clarification questions

"I'm rating the candidate on their ability to:

Prioritize the most important aspects of the case to focus on.
Employ active listening, including asking good clarifying questions and summarizing key points.
Ability to build rapport and collaborate with the interviewer as a partner in solving the problem."

Adrian, ex-BCG associate director.

2. Create a case framework

It's time to give your thinking a clear structure. You're going to create a framework, and this will be the foundation that will structure your thinking for the rest of the interview. It will also demonstrate that you have the ability to break down complex problems into manageable components.

The kind of framework you create will depend on the type of case problem you're given but most of the time you'll create an issue tree. You'll need to make sure that your issue tree is both MECE and 80/20. Read more about using issue trees in case interviews.

You might want to base your issue tree on one of the common case frameworks:

These pre-existing frameworks can be a useful starting point. However, DO NOT simply copy an existing framework. Interviewers immediately spot and penalise candidates who do this because the objective of the framework question is to test your creativity and business acumen – not your ability to memorise frameworks!

In any case, in our experience (we've helped thousands of candidates get MBB offers) pre-existing frameworks are bound to produce average results because all cases are unique.

Your framework should be tailored to the specific case, but it doesn't need to be complicated. Look at how simple the below framework is.

When you've created your framework, talk the interviewer through it.

Approach

"I'm rating the candidate on:

ability to break down complex problems into manageable components.
use of structured frameworks or methodologies to approach the problem.
ability to clearly articulate their approach."

Adrian, ex-BCG associate director.

3. Explore your framework

Once you've explained your framework to the interviewer, you'll want to start exploring it. The best way to do this is usually by making a hypothesis. State a hypothesis that seems most likely, given the information available.

Think aloud as you start exploring this hypothesis. Ask the interviewer questions to explore whether your hypothesis is valid. If you conclude that your hypothesis is false, eliminate that branch and go to the next one.

"In general, being hypothesis-driven is a great way to approach cases. It helps you start formulating potential answers early on, and it helps you narrow down the list of criteria that could be driving your answer." John, case coach and ex-Bain manager.

Framework exploration

"Throughout the interview, but especially during this stage, I'm rating the candidate on how well they:

identify key business drivers and factors that affect the client’s business.
make decisions under uncertainty or with incomplete information.
justify decisions with logical reasoning and supporting evidence.
evaluate the potential risks and trade-offs associated with different options.
show flexibility by adjusting their approach based on new information or feedback."

Adrian, ex-BCG associate director.

4. Do the maths

Now you're deeper into the analysis of the case, it's almost certain that you'll come across some calculations that you need to make.

You might be provided with additional charts and data (McKinsey) or you might be asked a quantitative question with no data provided (BCG, Bain), such as "Could you estimate the market size for cars in the US by making assumptions?".

Calculators are not usually allowed in case interviews. This applies to both in-person and virtual case interviews. That’s why it’s crucial for candidates to practice doing mental maths quickly and accurately before attending a case interview.

Unfortunately, doing calculations without a calculator can be really slow if you use standard long divisions and multiplications.

Luckily, there are some tricks and techniques that you can use to simplify calculations and make them easier and faster to solve in your head. We cover them in our free guide to Case interview maths.

Don't forget that when you've run the numbers and got your results, you'll need to interpret those numbers, What do they mean for the client's business? Do they support your hypothesis? What course of action do they support?

Maths and analytical skills

"I'm evaluating the candidate on:

quantitative analysis: are they comfortable with numbers, can they perform quick calculations?
data interpretation: have they shown an ability to analyze and draw insights from data?
logical reasoning: can they make local connections and conclusions from the information they've been given?"

Adrian, ex-BCG associate director.

5. Brainstorm solutions

Depending on the type of case problem you're given, you may reach a moment near the end of the case where you're required to brainstorm potential solutions, problems, or causes.

For example: Now that we know that the profit decline is driven by a decrease in the number of SUVs sold, what are some of the ideas you have to turn the situation around?"

This type of question is very open-ended. There are no right or wrong answers. It's testing your ability to generate new ideas and solutions in a pressured environment, but you need to do this in a structured way, rather than just throwing some ideas around.

When you're at this moment in the interview, ask for a minute to gather your thoughts and create a mini-framework before you start coming up with solutions.

Here your "framework" can be extremely basic. For the example we gave above, you could create two buckets - sales/marketing ideas and product ideas - and then come up with a couple of suggestions for each.

Solutions

"I want to see creativity and innovation from the candidate here. I'm hoping to see them:

think outside the box and propose unconventional solutions.
generate new ideas that can create additional value for the client."

Adrian, ex-BCG associate director.

6. Make a structured recommendation

The last component of every case interview is the recommendation. As the name suggests, this is the part of the interview where you’ll be asked to summarise your findings and explain what the client should do.

When asked to give your recommendation, don't jump straight in. Ask for a moment to gather your thoughts. Then:

Give your recommendation first
Then provide 3-5 supporting arguments
Outline next steps and potential risks

Consulting is a time-scarce business, so you need to get straight to what's most important. In the same way a newspaper story starts with the headline, you give the recommendation first, then provide supporting arguments.

If the interviewer challenges your recommendation, listen to their argument and be prepared to adapt. However, keep in mind that some interviewers will challenge you simply to see if you have the backbone to defend your ideas when you're confident of being right.

Recommendation

"I'm rating the candidate on their ability to:

summarize key findings and insights succinctly.
provide a coherent and logical conclusion that addresses the client's problem.
formulate clear and actionable recommendations based on the analysis, and justify their recommendations persuasively.
handle objections or challenges from the interviewer professionally."

Adrian, ex-BCG associate director.

Right, now you've learned a structured approach to case problems, you can start putting it into action on example cases.

Step 3. Solve practice cases (33 free example cases)↑

The best way to master the case interview process we've outlined above is to practise with realistic example cases.

Below are several example cases for leading consultancies to get you started.

If your target firm isn't included above, or if you want even more practice cases, check out our list of 47 case interview examples. This list includes free cases for other firms like Accenture, Oliver Wyman, PWC, Roland Berger, etc. There are several more McKinsey cases there as well.

Step 4. Improve your case interview technique↑

Interviewing is a skill in itself, and that applies even more so when you're in a case interview. So once you've practised using the methods we outlined above, take the time to polish your interview technique and make sure you're following these best practices:

Tip #1: Listen carefully and ask clarification questions

At the beginning of the case, your interviewer will lay out the situation of the company you are trying to help (e.g.: Coca-Cola's profits have decreased by 10% over the past 12 months). Your job in that part of the interview is to make sure that you understand the situation correctly by asking the right clarification questions (e.g.: In which countries have profits declined? And for which products?).

This is what partners at McKinsey and other firms do with clients. They sit down with them, listen carefully to the problem they have, and ask clarification questions before trying to solve the problem. They do this because it's impossible to solve a business problem you don't understand in detail. And you should therefore follow a similar approach in your cases.

Tip #2: Structure, structure, structure

Once you understand the situation in detail, your interviewer will expect you to put together a framework that you will use to solve the problem your client is facing. For instance, if your client is facing a profits issue, your interviewer will expect you to look into 1) potential revenue issues and 2) potential cost issues because profits issues can be due to one or both of these factors.

Consultants use frameworks to structure their thinking all the time because it's client-friendly. If you don't solve the problem in a structured way, your client will probably lose track of what you are doing and be unhappy. If you solve it in a structured way, they will know what you are working on at all times and feel that you have things under control. Interviews are the same. If you structure your approach and communicate in a structured way, you'll have a happy interviewer!

Tip #3: Don't reuse frameworks

We mentioned this in section 2 but it's worth repeating because so many candidates fall into this trap: don't reuse generic frameworks. As we explain in our case frameworks guide, interviewers will immediately notice if you do this and you will get penalised. Each case is unique, and you should therefore create a custom framework for every case you do. This might sound difficult, but it actually isn't if you take the right approach.

Tip #4: Think before speaking

Consultants sell advice. Once you have said something, it's hard to take it back. One of the things you learn as a junior consultant is to think first, decide how you are going to say what you want to say, and then finally say it. If you can do that well in your interviews, it will truly set you apart. In practice, it means that you should take some time to organise your thoughts before speaking and that you should avoid jumping to conclusions.

Tip #5: Try to convey confidence

We know this one is hard, but conveying confidence can make a big difference in your interviews. We all have doubts, and we are all stressed when we interview. It's perfectly normal. But you should try to keep these doubts and stress to yourself. You should try to look your interviewer in the eye and speak as confidently as possible. Conveying confidence is a core consulting skill and if you can do it in your interviews, it will take you a long way!

Tip #6: Brush up your maths

Virtually all case interviews involve doing maths computations without a calculator. Having rusty maths at the beginning of your preparation is normal. But in our experience, successful candidates take some time to brush up their maths when they start practising. You should take the time to refresh your memory and be 100% comfortable doing basic additions, subtractions, divisions, multiplications, and growth rate calculations mentally. We really encourage you to take the time to do this. Trust us, it's worth it!

Tip #7: Don't calculate silently

When you're on the numerical part of the case, it can be tempting to go quiet as you do calculations in your head. This is a mistake. "It's much better if you can keep your interviewer engaged in your thought process and speak your calculations out loud," says Garvit (ex-interviewer at EY).

Tip #8: Draw conclusions

As we mentioned above, consultants get paid for their advice. One of the things clients hate is to pay a large sum of money and not get a clear answer about their problem. Even if they are halfway through the project, consultants avoid telling their clients: "We don't know yet." What they say instead is: "Based on what we have seen so far, our current hypothesis is that the profit decline you are experiencing is mainly driven by the Chinese market. We think this is the case for 3 reasons. Reason #1 is etc."

You need to do the same thing in your cases. At the end of the interview, your interviewer will ask for your conclusion. You can't dodge the question. You've got to give a clear answer with supporting arguments based on what you have learned doing the analysis. The trick is to caveat your answer with a sentence such as "Based on this initial analysis, etc." And to also highlight additional areas to explore to confirm that your current understanding is the right one.

Tip #9: Catch the hints

99% of interviewers have good intentions. They're here to help you perform at your best. During your interviews, they will give you hints about whether you are doing well or not. If they try to steer you in a direction, follow them - they're trying to help you. This might sound obvious, but candidates sometimes get so stressed out that they don't pick up on the hints interviewers give them.

Tip #10: Read up on business events

To pass a case interview, you don't necessarily need to be up to date on the latest business deals, but you can sometimes impress the interviewer if you bring in real-world knowledge. "I recommend to candidates that they try and know a bit about everything. Understanding current business and economic trends will help," says Adrian (ex-BCG interviewer).

Demonstrating interest and an ability to discuss business topics can also help answer fit or PEI questions.

Tip #11: Do targeted drills as well as mocks

You'll want to do plenty of mock interviews as part of your preparation, but don't think that you should only practise full-length interviews. John (ex-Bain manager) recommends doing targeted drills to ensure you are improving on your blind spots. He says, "For example, if you are consistently strong at chart clearing and brainstorming, but you tend to omit key points in your framework and often make one or two math mistakes, you need to focus on specific exercises targeting framework improvement and math accuracy."

Tip #12: Prepare properly for fit/PEI questions

The first 15 minutes of most case interviews is usually a "personal experience interview" where you'll be asked questions about your experience, motivations and working style.

Don't make the mistake of thinking these questions aren't important, they are. Use our guide to answering PEI questions (written for McKinsey candidates but relevant to all) to prepare.

Step 5. Practise, practise, practise↑

We've coached more than 15,000 people for interviews since 2018. There are essentially three activities you can do to practice for case interviews. Here’s what we've learned about each of them.

5.1 Practise by yourself

We recommend that you practise by interviewing yourself out loud. Play the role of both the candidate and the interviewer, asking the questions and answering them, just like you would in an interview.

This may sound strange, but it will help you master the rhythm of case interviews. It will also help you to memorise the key details of your answers to behavioural questions, without any crutches (like notes, glancing at your resume, etc.).

As you go through this process, if you'd like a broader list of questions to practise with, you can check out our consulting interview questions article.

Of course, by yourself, you can’t simulate thinking on your feet or the pressure of performing in front of a stranger. Plus, there are no unexpected follow-up questions and no feedback.

That’s why many candidates try to practice with friends or peers.

5.2 Practise with peers

If you have friends or peers who can do mock interviews with you, that's an option worth trying. It’s free, but be warned, you may come up against the following problems:

It’s hard to know if the feedback you get is accurate
They’re unlikely to have insider knowledge of interviews at your target company
On peer platforms, people often waste your time by not showing up

For those reasons, many candidates skip peer mock interviews and go straight to mock interviews with an expert.

5.3 Practise with experienced MBB interviewers

In our experience, practising real interviews with experts who can give you company-specific feedback makes a huge difference.

Find a consulting interview coach so you can:

Test yourself under real interview conditions
Get accurate feedback from a real expert
Build your confidence
Get company-specific insights
Learn how to tell the right stories, better.
Save time by focusing your preparation

Landing a job at a top consulting company often results in a $50,000 per year or more increase in total compensation. In our experience, three or four coaching sessions worth ~$500 make a significant difference in your ability to land the job. That’s an ROI of 100x!

Click here to book case interview coaching with experienced MBB interviewers.