To the uninitiated, the case interview can be more than a little bit terrifying. The main point of the case interview is to provide you with an opportunity to show the interviewer the great job you’d do if they hired you today and set you straight to work. Part of that, is showing them your command of case interview math.
Here at Management Consulted, we have thousands of hours of experience in this area because we were established and run by MBB consultants, AND we do 1000s of case interviews a year. Not tens, or hundreds, but thousands.
Not only that – we’re here to help you succeed, and dedicated solely to consulting candidates. With all the tips we give you here, it’s important you practice them to help you avoid huge missteps in real case interviews. Once you master these tactics, you’ll be much better equipped for any and every case study that gets thrown your way.
1 – Mental Math Consulting
We can already hear some of your hearts sinking into your stomach as you read that. We’re sorry, but it’s something that comes up over and over again. It may be required of you in a sizing question or in a case study, but no matter what, you won’t get into a top consulting firm if you can’t demonstrate acuity with case interview math.
If you don’t like case interview math, especially mental math with large numbers, then PRACTICE! Even if you feel numerically challenged, practice! Test yourself over and over again in this area and make sure you continue to wean yourself off Excel and your calculator. As with any muscle, it will grow stronger the more you use it.
There are 2 aspects of inspired mental math – accuracy, and speed. Accuracy comes by developing a process, practicing under simulated conditions (e.g. out loud, with a timer), and taking great notes. Accuracy is more important than speed – without accuracy, speed is nothing.
Speed, in contrast, is icing on the cake. Top candidates demonstrate the ability to boss around numbers. They use them in casual speech. They think numerically. Case interview math is a fun game they play, and they actually enjoy the math section of the case. Speed comes through short-cuts and strategies, but mostly just through confidence – you hear a problem, you make a plan, and you dive right in.
2 – Identify The Question’s Objective
This is a very important weapon to have in your case interview arsenal. It’s not unlikely that you will get asked at least on very broad and open-ended question in each case interview. The temptation, especially if you’re feeling nervous, will be to jump in head first and hope for the best.
There’s a problem with this method: the chances of you going off on a complete and unnecessary tangent are high. Too high. Time is an important issue in case interviews, so you don’t want to waste it. Remember, spending a few extra seconds at the beginning of each question getting to the heart of the issue can save you valuable minutes later on.
Whether you are opening the case, where you must make sure you understand the case context and background, or mid-case, where you want to make sure you’re driving toward the correct conclusion, don’t just ask if there are other objectives. Give it a college try by offering a choice or suggestion about what you think the interviewer is asking.
If you do get asked a very broad and open ended question, you have a great opportunity to shine and demonstrate a level of incisive, analytical prowess that not all candidates will possess.
A quick example of this could be the interviewer asking you;
“What issues do we need to better understand here?”
To which you might reply;
“Are you looking for company specific issues, or industry wide problems?”
3 – Never Confuse Company-Specific And Industry Wide Problems
If you ran the risk of doing this, we just saved your bacon. You’re welcome. If you did happen do confuse the two in a case interview you practiced before, we’re sure you understand how far off course this could take you.
Make sure you differentiate between these when you’re trying to diagnose issues. For example, you may be given a case interview about a car company who came to the firm because their profits are suddenly declining. An example of company specific vs. industry wide problems may be:
Company-specific – The company using very expensive raw material to build their cars, leading to very small profit margins.
Industry-wide – Three of their main competitors have released similar performance cars recently, all of which are cheaper than theirs, and they are losing market share.
We usually recommend focusing on eliminating industry-wide problems first – if they aren’t there, you can dive more deeply into company specific problems. If you do uncover an issue, you can explore the company’s position first before identifying recommendations.
4 – Segmentation
This is vital. If you’re trying to get to the heart of the issue, you must remember that you cannot just use a one-size-fits-all label, “customers” or “products/services”. It would not be fully accurate to work from the assumption that the only thing happening is general decline in revenue across the customer base, or across all products and services.
It is very unlikely that all customer or product segments are being impacted in the same way. In keeping with our example of the car company, it may be that they have actually seen a 10% increase in purchases among 35-50 year old men, while seeing a 60% decrease in purchases among women in the same age range.
What are the insights? What they’re doing is working among men, but is failing among women. If women used to make up 75% of their clientele, this accounts for the oversized downturn in their revenues and related profits. But not only that: it gives us insight on how to fix it – targeting the women either with the old strategy/message/process, or dividing them out to understand them better going forward, or both.
Common types of segmentation are: product segmentation, customer demographic segmentation, customer needs segmentation, channel segmentation, and geographical segmentation.
5 – Have An Opinion And Stick With It
By the time you’ve finished all of your deliberations, considering all the data that has been put in front of you, can you come to a conclusion and summarize it?
The vast majority of interviewers are going to shoot from the hip and ask you to tell them exactly what you think at the end of each question and at the end of the case. This isn’t the time to tell them what your notes say, but for them to hear what you think. Here, it’s important you don’t beat around the bush and ask for time, but that you just spit it out (McKinsey is the one exception – they don’t mind as much if you do take time).
This also isn’t the time for you to be shy. Be confident and give your answer in the self-assured manner that is befitting of a case interview genius.
However, if you’re concerned about the issues that may arise from closing with guns blazing and being horrifically wrong, remember: consultants are simultaneously confident and risk-averse. Soften your language to leave room for suggestions, but don’t be too weak – explain what research you’ve done, present a conclusion, and provide next steps.
We hope this has been helpful to you. If you would like a lot more information on how to succeed in case interviews and case interview math, we have many great resources available to you, including our book, The Consulting Interview Bible, which can be purchased here.
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