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consulting interview prep

How to prepare for your consulting case study interviews?

“Ah! One of the most frequented questions among consulting candidates. I remember when I started my preparations, I faced so many of these questions. How many cases should I do before the interview? With whom should I prep cases? How to train my case solving abilities? I found different answers online with diverging reasons, but what I can do now is look back and tell you my experience regarding these questions.”

How many cases should you do before the interview?

After a few cases, most candidates will start looking for an optimal system, a structure to their preparation. They will start to look online or at their peers for the answer of how many cases should they do before the interview? 5, 10 or 100? What would make the most sense? Does only a case a day keep the offer away? If so, how many should I do in a week? Well, the answer might not be super linear at different stages of your preparation. During my case solving sessions, I started noticing that early on, I was practicing cases just to get the gist of how to talk to the interviewer, which questions to ask before doing the deep-dive, how to switch from an issue tree to my statements and so on. I felt like early on a larger quantity of cases a week definitely helped me to get a nice flow during my analysis and briefings.

Now what changed during my preparation phases, is when I started getting better at cases, I started noticing some returning problems to my cases, which were a bit harder to overcome. My issue tree briefing was not structured enough and I jumped between buckets or my exhibit reading was a bit lackluster and most of the times I made errors because of that. So how did I change the quantity of the cases? Well, I actually did half as many cases as I used to before, and started focusing narrowly on my prevailing problems. Everytime, I asked my coach to actually get cases which will thoroughly test my ongoing issues and we took 30-40 minutes after every case just to analyse how I performed and how to actually counter some of the shortcomings. In this way, even though the number of cases done in a week were lower, I focused on my prevailing problems and finally overcame them.

So what is the final verdict? Well, while there is no magic number for the number of cases done in a week, I would recommend to up the frequency early on, just to get a hang of the structure, talking, calculations and so on. Consistency is key, so at least one case a day. Later on, when you feel already confident, start focusing on your weaknesses and cut down the number of cases, but spend twice as much on each case. Set a goal for yourself on what to change, try to execute it and afterwards analyse the results. The key here is to perfect your case solving abilities, let it be the structuring, calculations or summaries. Some friends may perfect these skills after a few cases, I know some university peers who practiced for 5 months and finished around 100 cases.

With whom should you practice cases?

A very well debated question again. Most of the sources online will either tell you that it is fine to practice cases with your friends and family, while others will urge you to only practice with professionals, as non-competent “interviewers” will not help you solve a case better. Again, I would like to share my experience with you, as I have tried both options.

Starting with people who are not exactly familiar with cases: Now, back when I was prepping for my interview, a few times I practiced with my brother, who is a law student and had literally no clue about consulting case interviews. After a long and painful explanation period, he got the main idea behind the cases, and was able to conduct the whole procedure. While this was definitely a useful way to practice speech and flow, it certainly came with some problems. The cases were very straightforward and there were no twists or cross-questions to test my ability to hold my structure together. A seasoned interviewer could certainly ask me questions that would either create some doubt in my structure or suggest some other ways to tackle the problem, which will happen in real case interviews. My brother or any other non-familiar person could not recreate this back and forth conversation.

Then I practiced with other students, who had a business background and were somewhat familiar with business case studies. I must say it was much better than doing the same with my brother, but it was not professional at all. Other students, or your friends, will make you way too comfortable, you will not feel the pressure from the interviewer. The pressure under which you will need to perform at least 6 times to get an MBB offer. Since we had the same background and the same level of experience, we could not dig into details, it felt like we were blindfolded. Being biased was another pain point. It is extremely difficult and rare to give and receive critical, constructive feedback from people, who are close to you, or from those who do not really know what they are doing.

On the other hand, while I was prepping with a professional case coach, I was not only challenged on my ideas and had to provide a logical argument why my approach is valid, I also felt a psychological pressure just from the sheer fact that I cannot slide over anything, like I could with a “non-familiar” person. You see, a structural mistake or a logical error might not be noticed by your peers and both of you can just “glide over it”, while a professional coach will plainly challenge anything that he doubts, so you must always be prepared to provide a sound argument to back up your claims. “Why is that?” “Are you sure?” “Elaborate on it please!”. Expect these quick cross-checks from your coach.

Now, the bottom line is the following: While a “non-familiar” person can actually help you just to get going with cases, practice the flow and the structure of a case, your skills will reach their limit quite quickly and you will need to seek someone who is well-seasoned in cases. I know that solving a case with a stranger might be daunting, but it is the way to go if you want to land those sweet offers from your dream consulting firms. While they might be pricey, you definitely need more experienced teachers to learn from.

How to train my case solving skills?

This is a question that actually came up frequently, when I first started coaching a friend of mine for their consulting interview. There are actually quite a few ways to enhance your problem solving skills other than case interviews, which don’t even require anyone else than you to train.

Mental math

Sounds simple? It is, however, quite efficient to practice your mental math. Especially try to come up with ways to simplify any problems that you have. It is indeed a quite simple trick but you force yourself to come up with different approaches to quickly solve problems in your head, which in turn can truly help you to be more creative. This can come in handy when you face a complex and rather hard case and can cut down the time for you to come up with a sound approach. I encourage you to practice GMAT math questions.

Self-structuring

Another extremely effective way to enhance your problem-solving skills is to create self-structuring exercises that will improve your time needed to create a cohesive and concise structure to any problem. One of the easiest ways to practice this skill is to think of an item and try to sort its components in MECE (Mutually Exclusive Collectively Exhaustive) groups. For example, how can you categorize pizzas? Vegetarian and Meat-based? Well, they could also be salty and sweet pizzas. Try to think of many ways and build a MECE tree which has at least 2-3 layers. You will definitely see the improvements immediately. How to improve your self-structuring skills? The key is a professional, who can give feedback on your structure, as well as: practice, practice, practice.

Communication

Lastly, you should put emphasis on your communication abilities. Both interviewers and clients will highly appreciate an individual with great rhetorical abilities. What I would recommend is to always speak out loud when you are practicing cases. Try to record yourself summarizing a prompt or even an entire case, re-watch it and then look for mistakes and improvement points. You will quickly start to get the hang on how to perfectly summarize entire cases, without jumping back and forth between prompts and leaving out important data or findings.

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This article is part of a series of introductory articles:

  1. Why management consulting? What do consultants do?
  2. Why should you pursue consulting?
  3. How to write a management consultant resume?
  4. How to write a management consultant motivation letter?
  5. How to prepare for your case interviews

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