15 case interviews tips for McKinsey, BCG and Bain

Case interviews tips for McKinsey, BCG and Bain (MBB)

If you are targeting a job in consulting, you probably already know what type of interviews to expect: a case.

In a case interview, your interviewer will ask you to solve a business problem. For instance, they might ask you how Coca-Cola could double their profit margin next year. Cases have got the reputation to be amongst the most challenging types of interviews and candidates tend to fear them. But it doesn't have to be that way.

Over the past few years, we've helped more than 20,000 candidates prepare for consulting interviews. We've learned about what works and what doesn't. We have also analysed all the case interview advice from McKinsey, BCG, Bain, Deloitte and other sources.

In this article we summarise the most important tips we have learned along the way. So let's get started!

Click here to practise 1-on-1 with MBB ex-interviewers

1. Preparation tips

It all starts with a good preparation. Here are a few tips you should follow to structure your consulting interview practice.

Tip #1: Start early

This might sound obvious, but case interviews can be challenging, so you should start preparing early. Some of the people we work with start studying up to 6 months before their interview. Starting that much in advance is not necessary to get an offer, but the earlier you start the higher your chances of getting an offer are.

Tip #2: Learn the fundamentals

The first thing you should do is learning the key concepts and core skills you need to get an offer in consulting. In other words, you need to learn the fundamentals. This website has many free resources you can use to do this. We recommend starting with our free case interview guide and our list of free case interview examples.

Tip #3: Practice with peers

Practicing with peers is useful to get live interview practice. This is something that is common on university campuses and is often organised by consulting societies.

If you are not already doing so, we definitely encourage you to find one or a couple of friends who are also preparing for consulting interviews and with whom you can practice. You will learn a lot both by playing the role of the interviewer and the candidate. Here's a list of consulting interview questions you can practice with.

Tip #4: Practice with experts

Practicing with peers will only get you so far. If you really want the best possible preparation for your case interview, you'll also want to get feedback from ex-consultants who have experience running interviews at McKinsey, Bain, BCG, etc.

If you know anyone who fits that description, fantastic! But for most of us, it's tough to find the right connections to make this happen. And it might also be difficult to practice multiple hours with that person unless you know them really well.

Here's the good news. We've already made the connections for you. We’ve created a coaching service where you can do mock interviews 1-on-1 with ex-interviewers from MBB firms. Learn more and start scheduling sessions today.

Tip #5: Keep it up

Learning any new skill has got its ups and downs. Mastering case interviews is no different. Your performance probably won't be amazing on your first few cases. You will probably make mistakes even after you have practiced 15+ cases. Keep it up. It might take a while but everyone can make it to consulting by following the right step-by-step preparation plan.

2. Case interview tips

Now that you know how to approach your preparation, let's focus on a few tips that you should use during your actual case interview.

Tip #6: Listen carefully and ask clarification questions

At the beginning of the case, your interviewer will layout 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 details. And you should therefore follow a similar approach in your cases.

Tip #7: 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 and 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 #8: Don't reuse frameworks

One trap many candidates fall into is to reuse pre-existing frameworks in their interviews. 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 #9: 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 #10: 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 practicing. 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 really worth it!

Tip #11: 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 #12: Catch the hints

Finally, 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.

3. Fit / PEI questions tips

In addition to a case, your interviewer will also ask you one or two behavioural questions. Let's turn our attention to those and go through a few tips that you can use to impress your interviewer.

Tip #13: Research consulting / the company

The two most frequently asked fit questions you will come across are "Why consulting?" and "Why McKinsey? / Why BCG? / Why Bain?" You therefore need to do your research about consulting as well as the company and office your are interviewing for. Try to really understand whether consulting is a job you will enjoy doing. Try to meet consultants from the firm and office you are interviewing for. This will help you give genuine answers to these fit questions and will set you apart from other candidates.

Tip #14: Prepare for PEI questions

In addition to typical CV questions, consulting firms also ask personal experience interview questions. These questions are easy to recognise, they always start with: "Tell me about a time when..." They aim to test your soft skills such as your leadership or your ability to work in a team. A lot of candidates underestimate their importance and end up not preparing sufficiently for them. We recommend setting about 25% of your time to prepare for fit and PEI questions.

Tip #15: 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 really take you a long way!

4. Conclusion

When it comes to preparing case interviews, it can seem like there's a lot to take in. Even when you've covered everything mentioned above, it's still hard to gauge your level and to be sure whether or not you're really ready to ace your interview.

That's one reason why mock interviews are so helpful. If you're interested, click below to browse from our many ex-interviewers from MBB firms, and book your mock interview at a time to suit you.  Learn more and start scheduling sessions today.