I have to be honest: the case interview was one of the scariest things I’ve ever done. I was a nontraditional student trying to go into one of the most traditional careers out of business school, and I wasn’t quite sure I could do it. So I threw myself into preparation without thinking through the big picture: the purpose of the case interview, the metrics by which I’d be evaluated, and the skills I already brought to the table. I didn’t “structure the problem” at all, and as such, ended up wasting a lot of time and energy. So in the spirit of practicing smart (not just hard), here is the scoop on the case interview.
Why Case Interviews?
While many industries now use case interviews, the history of this storied experience traces back to consulting firms. Consulting is a profession that requires its talent to work well with ambiguity, to think on their feet, to keep their cool when clients push back, and to be able to frame a problem with hypotheses and ideas for analysis while given imperfect information. Sound familiar? Yep, it’s what you do in class every day (hence: “case method”). So if HBS students do this multiple times a day for months before recruiting week, shouldn’t we all be experts at this interview style? Well, not exactly.
There’s a big difference between “cracking a case” with 90+ sectionmates while a kind and benevolent professor guides you through the tricky spots and accomplishing such a task alone while staring down power-hungry interviewers who know they hold your future in their clammy, clenched fists. (In case it’s unclear: I’m mostly joking here – the interviewers are generally pretty awesome people outside their suites at the Charles Hotel.)
So what does this mean for you? It means preparing for the quant and thinking about the structure (more on this below) while keeping the intention of these interviews at the forefront of your practice. Show them how well you keep cool under pressure. Demonstrate that you notice important details or key assumptions in your analysis without losing the big picture. Flaunt your creativity and mental agility when they throw you a curveball. That’s how you convince them that you would make a great consultant.
There are two parts to most consulting interviews: the personal experience (or “behavioral”) interview and the case interview. While this article is focused on the case interview, it is imperative that you not neglect the other type. The personal experience interview is your chance to shine and showcase the traits that strong consultants demonstrate as well as to highlight your differentiation from all the other MBA candidates they are interviewing.
Within the case interview, there are generally two pieces: logic questions and business cases.
Logic questions are often referred to as “brainteasers,” and they generally revolve around market-sizing (for instance: “How many piano tuners are in New York City?”). While these are actively used in undergraduate interviews, they are much less common as stand-alone questions for MBA candidates. More often, they are embedded within the business case as a quantitative exercise. (To be honest, however, I didn’t get a single question of this sort across three firms and multiple interviews, so don’t be alarmed if you don’t face one.) The key to succeeding at logic questions is to realize there is no one “right answer” (although some answers are more reasonable than others-e.g., you wouldn’t want to make an assumption that the potential size of the diaper market in Florida is larger than the population of Florida); the point is for the interviewer to understand your thought process and agility with quick calculations. You’ll have to make a lot of assumptions, but just be clear on what they are; even better if you can point out how your answer would change if one or more of your assumptions doesn’t hold. Since you get to pick the numbers you are working with, pick easy ones to manipulate (10 is always better than 9.2, even if the latter is more precise).
Business cases are the meat of the case interview: they revolve around your “client’s” business problem that you have been brought on to solve. The case may be one the firm uses year after year, carefully prepared by someone in recruiting, or it could be a case based on the interviewer’s own client experience. It might be very straightforward, with carefully delineated questions throughout the process, or it may feel much more nebulous, with no clear path defined up front. Whatever the situation, the case has been designed to test three areas: problem solving / analytical skills, interpersonal skills, and leadership / effectiveness.
1) Problem Solving and Analytical skills: While quant is the first thing that comes to mind for most people, calculating 12% of 47 is not the only thing being tested here. Interviewers also want to see how well you frame the problem and whether you lay out a systematic and prioritized method to approach a solution. They want to see if you can formulate hypotheses and determine what kind of data would help you test them; if you can leverage solid business judgment to identify the areas where the answer is most likely to reside; and if you can push through the analysis to develop insights about the business, something often referred to as the “so what?” moment. These are considered the “hard skills,” and thus most candidates practice them the most. However, while they are critical to a successful interview, they are only one part.
2) Interpersonal skills: This is sometimes called the “communication” portion, but it actually encompasses so much more. Yes, they want to know that you can speak clearly and persuasively, listen actively (they are often dropping hints! be sure to listen!), and summarize effectively, but they also want to see enthusiasm and energy for the case. If solving problems excites you, let that shine! If you look like you are dreading the case from the moment you step in the room, you’re pretty much DOA (that is, dead on arrival). Finally, interpersonal skills include the ability to be flexible, most notably when they throw you a curveball by reversing one of the earlier assumptions or by adding a new condition to see if you can “roll with the punches.” In a nutshell, are you “client-ready”?
3) Leadership and Effectiveness: You may be wondering how one shows leadership in a case interview; isn’t that the point of the personal experience interview? Well, yes, but in that portion you can only describe your leadership skills. In the case interview you can show them. True, you need the interviewer to set up the situation, and she may jump in to guide you along the way, but you shouldn’t rely on her to tell you what to do. Instead, take a few moments to gather your thoughts and formulate a game plan for solving the case. Take charge of the interview; try to think of it as if you’re the consultant and your interviewer is the client. Tell her you’d like to look at costs before revenues because you suspect there might be something interesting going on in their variable costs. Describe the kind of data you’d want to collect in order to test your hypothesis, and if she has it, she’ll likely offer it at that point; don’t just verbally meander or ask repeatedly, “do you have data on X? What about data on Y?”
Everyone is going to prepare for case interviews a little differently based on the skills they already have and their natural strengths and weaknesses. Nonetheless, there are a few things I’d recommend:
Books: Get “Case in Point” and “The Vault Guide to the Case Interview” (By the way, “Case in Point” is free with membership in the Management Consulting Club. And no, I’m not paid to say that.) The advice sections in the books are pretty generic, but the practice cases are extremely helpful. Use “Case in Point” to get used to the thought process of a case, and read enough sample cases to internalize the standard line of questioning. Then use the cases in the Vault Guide for mock interviews.
Interview prep sessions: Go to the interview prep sessions for every firm with whom you have an interview. While the basic skills carry over from one interview to the next, each firm has a very different style, and it is in your best interest to get a feel for that style ahead of time. Similarly, most firms will hold mock interviews; this is the best opportunity for you to practice the real thing. It will surprise you how different each style feels when you are nervous.
Mock interviews on campus: In addition to the mocks held by individual firms, MBA Career and Professional Development gets ECs from consulting backgrounds to hold mock interviews. Your section might also pair up former consultants with those of you interested in summer positions to practice cases. Use these resources to your advantage! The least valuable mock interviews are generally those you hold with other potential candidates. While it might seem like good preparation, typically your partner isn’t able to give the kind of feedback that makes the time invested pay off. This is where I would draw a distinction between working hard and working smart.
Company websites: Most firm websites post sample interviews-this is another good way to become familiar with the nuances among firm-specific approaches. And if you’re a more “introverted” preparer, you can step through the solution a few times online before being put on-the-spot with live mocks.
Wherever you go and whatever you do between now and Hell Week, start thinking like a consultant. Are you annoyed at the long line at a sandwich place? Consider what you would suggest to improve its efficiency. Now what assumptions did you have to make? Under what circumstances might those assumptions not hold? How many people come through during the lunch rush each day? Does your recommendation make sense at that volume? What if the volume doubled? Halved? Getting used to this line of thinking when tackling problems will absolutely help you on interview day.
After all of this preparation you have just 30-60 minutes on the actual day to nail the interview. So what’s the key to amazing execution?
Confidence. Confidence, but not arrogance (there is an ocean between the two). Confidence to speak clearly and with authority. Confidence to smile and enjoy the interview, realizing that this is your chance to see what it’s like to work with this person (they could be a future teammate, after all). Confidence to breathe deeply and focus your energy on your interviewer, listening actively and developing a relationship that both gives and takes. Think of this like improv comedy or jazz music: you start with a premise (a riff, if you will) but you are building the performance with this other person; by staying present and listening you can react in the moment to body language or verbal clues and create a dialogue together. If you start talking and don’t stop until you run out of breath or 30 minutes is up (whichever comes first), you have lost the opportunity to engage your interviewer. And then it doesn’t matter if you know that 12% of 47 is 5.64.