Applications / Interviews

How to succeed in a consulting case study interview

Last time out, Florian from offered advice on how to prepare for a consulting career. This week he shares his perspective to help you perform confidently in one of the most important stages of the consulting recruitment process, the case study interview.

The set of skills you need to display in a case interview is the same as the skills needed in the daily life of a McKinsey, BCG, or Bain management consultant. The case interviews are basically a trial-run to gauge how well you would do in the actual job.

If you want to start learning these skills early on during your studies, it is important to understand on what dimensions the case interviewer will score your performance. If you understand what is important for the interviewer, you can tailor your preparation and put special attention to the points outlined below. I believe there are four key areas that you need to focus on:

Problem solving

Hands playing a cube gameThis includes problem structuring, creativity, and analytical rigour. One way to rise to the top of the shortlist of case interview candidates is to demonstrate a spike in creativity. When thinking about the problem and drafting your issue tree , go as broad and as deep as you can. Try to come up with as many different angles to the problem as possible (breadth) and draft rich descriptions that qualify why these areas are important to investigate (depth). Train this by taking a newspaper, frame every headline as a question or problem and think about what different elements you would like to investigate to solve that problem. Additionally, think about how to solve these issues most creatively.

Throughout a case interview, the structure should be the anchor that keeps you focused and on track. Initially, you need to structure your issue tree with each branch representing a part of the problem you would like to investigate. Devise a MECE (mutually exclusive, collectively exhaustive) approach, covering all aspects of the problem. Try to use this approach in everyday life when facing a problem or a question (e.g. evaluate decisions or solve questions by approaching them in a structured way, writing down the different elements to consider). Using this approach, you will significantly increase your chances to understand the root cause of an issue and improve your problem-solving skills.

The analytical rigour links the structure to creative thinking. Employ a hypothesis-driven approach in your problem solving, i.e. have a clear picture of where you think the solution of a problem is buried. This way, you will be able to qualify your thinking. Follow your structure – tackle (likely) high-impact issues first; lead your team effectively in the progress; and ask the right questions. Make it a habit to approach problems this way.

In general, read through business cases and attend case competitions. Become comfortable with structuring problems visually. The more exposure you get to tough problems, the better you build your ‘mental muscle’ in this field. 

Mental mathematics and basic calculus.

Math mathematics formulas exam science idea innovation head silhouetteThere are two parts to the question when cracking mathematical problems during a case interview. First, to solve a specific problem, you are often asked to derive the correct approach to calculate your desired outcome variable. You need to structure your approach before doing the actual calculations. Watch for different measurements. Even the simple computations often include some unexpected twist. Second, you need to make calculations relying on basic pen-and-paper mathematics. Incorporate some pen-and-paper and mental exercises into your studies. Let go of Excel or the calculator and do some calculations manually! Additionally, practice percentages and ballpark estimates whenever possible. You want to train this muscle and be ready when the case interviews approach. Many otherwise stellar candidates often fail due to simple calculation errors under stress.

Communication and maturity

Communication is very important since you need to be able to elicit the right information as well as convince the interviewer about your recommendations. Consultants always communicate top-down. When making a statement for example, start with a key fact, then provide supporting information for it. You’ll ensure that your statements are to the point and prevent endless rambling about a certain topic. Time is limited and you want to get your point across in a concise and structured manner. You can focus on this skill during university presentations and classroom discussions. Structure your presentation files, speaker notes and messages top-down. Whenever there is a chance, volunteer to present in front of larger audiences. Look into the ‘pyramid principle’ or similar communication frameworks like our own SCORE framework on to further your understanding of top-down business communication.

And finally, business sense and intuition…

ReportWhile you are certainly not expected to know details about a certain industry or specific context of the case, you need to be able to demonstrate business sense and intuition, which is very much related to common sense and acquired knowledge. You should be able to quickly understand a business – even just by asking targeted questions – about how a specific business works, what its business model is, what the main cost drivers are, and how the business makes money.

Use your common sense or experiences/ knowledge with other industries or contexts to explain certain phenomena in the case, when coming up with assumptions, for example. Coming from a business school can give you an advantage over other candidates in this dimension. But if you are not studying a business related subject, make it a habit to read the Economist, the Financial Times, and the Wall Street Journal, for  example, to get confronted with as many business problems as possible.

Obviously, following these guidelines is just a first step to develop the specific skills needed in the consulting interviews. When you apply to consulting firms, there is much more to the preparation. You would still need to learn about case interview methods, as well as practice and prepare properly. We recommend at least 4 weeks to practice cases for the top firms. However, if you have already established a solid foundation during your studies, your case interview practice will be much more efficient and your interview outcomes much better. The earlier you start, the better! offer a variety of free tutorials and articles on consulting applications and case interviews, and are the first organisation to offer detailed guidance on  McKinsey’s digital assessment  by Imbellus (gamified assessment)


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