How To Master Your First Case Interview

During the full time job and internship hunting season, one question always comes up in my inbox from aspiring consultants:

How the hell do I prepare for this Case Interview?

How does Mckinsey differ from IBM? Deloitte? PwC?

The case interview, despite its ubiquitous use as an interview vehicle, can be one of the most daunting parts of a consulting interview. With behavioral interviews, you can often practice and rehearse stories that come from your own empirical experiences. If you can’t, you can bullshit a story about how you were a good leader from the confines of a reality that can’t be challenged by an interviewer. A case interview? You will know nothing until two minutes before it happens.

So how do you even start?

First, a few caveats:

  • Every company will have different ways of doing case interviews. I would focus on general preparation instead of focusing specifically on a company (i.e. Mckinsey) or a format.
  • Cases can be interviewer-led, candidate-led, or group cases. Prepare accordingly. Make sure you make meticulous notes and don’t interrupt when it’s interviewer-led, don’t dominate consistently if it’s group led, and don’t panic if it’s candidate-led.
  • Remember that doing well on a case does not save you from poor performances in behavioral interviews. I’ve learned this from personal experience.

That all being said, I’m a huge fan of Victor Cheng’s resources and have found his case interview frameworks to be some of the most helpful resources I’ve encountered in my resource hunt. A lot of people will mention “Case in Point” as a lead, which I have read and do find to be very useful, but also makes you over think beyond reason. Before even diving into tips to curb brain teasers and complex numbers, it’s best to know what a case interview’s goal is from a conceptual standpoint.

As the interviewer, your goal is to see how a candidate approaches an entirely foreign situation from a business perspective. Not to see how fast a candidate can do math or what esoteric facts they know about cottage industries. It’s to see how they can walk into a random situation and walk their way out.

Victor Cheng ( ) breaks it down into a few different frameworks depending on the type of situation, examples including:

  • Profit/Loss Framework
  • New Market Entry
  • Product Growth
  • Mergers and Acquisitions

Let’s say you get a sample situation: I am a large telecommunications company looking to expand our new cable box into the Philippines Market. I need to decide whether this market is worth entering.

Depending on whether it’s interviewer-led or candidate-led, you might get a bit more information than that. Let’s say for now, that’s all they give you off the bat.

Where do you go from here?

Like any other interview, prepare before the case even starts. Look polished, smile, and engage the interviewer before the case begins. It won’t save you from a failure, but could definitely add or two bonus points on the test of whether you’d be a gregarious consultant.

Repeat the case back word for word and clarify every objective. There is nothing worse than providing a recommendation for the wrong scope. (According to this situation, my primary objective is to validate whether or not the Philippines is a good market for this product. Am I also validating whether or not the product is worth building? or has this decision already been made?

At this point, validate the framework. This framework is clearly a Business situation, a ‘New Market Entry’ problem. You can find this on the second page of Victor Cheng’s PDF where he then leads you to some factors you can think about:

  1. Customers
  2. Product
  3. Company
  4. Competition

Take a minute and determine which questions you’re going to ask. If you have no questions after the initial case is presented, that is a red flag. Unless the interview has given you a sheet with all the data, they are expecting that you will ask some questions to further reveal more about this situation. Remember, treat the case as a foreign case. It doesn’t matter what you know about the telecommunications industry or the Philippines of the top of your head, if the information is not directly given, do not assume it. Given your framework, you can begin to think about questions for the following:

  • Customers: What is the growth rate of cable use? What price is each customer segment willing to pay for cable? What is the cost of switching? What is the primary distribution channel? Are we looking only at consumers or businesses? What are the socioeconomic characteristics of individuals who do have cable?
  • Product: What are the benefits of our product? Where is it in the product lifecycle? Are we vulnerable to substitutes? Will we be impacted by streaming companies? Can we bundle options to include phone?
  • Company: Can we assume our company is similar to a Verizon or Comcast? What is our company’s brand image? Have we entered new markets before? What is our previous retention? What is our financial situation? Is this market entry a make or break? What has the R&D invested in researching this market?
  • Competition: Is there a monopoly on the cable market? Any other foreign competitors we should worry about? Any barriers to entry? Legal barriers with the government? Industry regulations?

As you begin to frame questions, start thinking out loud and clarify assumptions. Remember, a case interview is designed to learn how your brain thinks. Thinking out loud helps the interviewer learn where you would start your reasoning and why you are choosing the questions you choose. If you start out by saying “Because this is a new market situation, there are a few specific things I want to think about: Customers, Product, Company, and Competition”, you’ve just likely won yourself a smile or a meek grunt of approval. Now, remember, if there is a comparison you want to make that is not in the given case, ask if it’s safe to assume. (i.e You mentioned that we are a large telecommunications company. Is it safe to assume that this company is similar to a Verizon or a Comcast?)

Engage with the interviewer. At this point, the interviewer will intermittently intervene. They will tell you that you’re perhaps asking a wrong question or will answer your question with more data or affirmative response. Make sure you thank them for the feedback and absolutely do not go back to a question that the interviewer mentions is not useful.

Make sure you’re careful when doing math. Let’s be honest, no consultant is going to be crunching numbers in their head. They are likely going to using a SQL database, Excel formula, or calculator. What the interviewer is testing for is whether you are using the right numbers — they could care less about how fast you complete a calculation. If you are on the right track with a data outcome, take your time and get the right number. You’ve already won half the battle by choosing the right data points.

Circle all recommendations back to the goal. Before presenting any recommendations, make sure you reiterate the goal. As we clarified before, the main focus of this case is to decide whether or not it is worth entering the Philippines Market. Because of what I found with *list findings from questions here*, I would recommend we do not. The legal risk is too high and there is a monopoly on the cable market etc. etc.

Make sure you also confirm what you don’t know. Any real business situation such as this one will take months. If there are any questions during your interview that did not have answers, clarify that information. I know you mentioned that we don’t yet have a price point available and I was not able to use this information to make a recommendation. This is information that would be useful for the future.

Thank the Interviewer and ask for post-case feedback. Once the interview is over, your interviewer will likely take a few notes and ask if you have questions. Asking simple questions such as “Is this similar to a case Mckinsey has done before” or “What is one question you would’ve asked that you didn’t hear?” can be good questions. It’s okay to present any questions that would open vulnerabilities, it shows that you are willing to learn and open to criticism.

Breathe. Before, during, and after. Even if you don’t get to a recommendation, the questions you ask may have been valuable enough for them to see potential in you. Remember that a case interview is only a microcosm of a real business situation to a certain extent — no real consultant comes up with the data and convictions to make a recommendation in 30 minutes. Just be confident in your questions so they know how your brain structures a strategic approach. No bad question is the end of the world.

Deloitte’s website also has a few really helpful tips:

Given what you now know, tips:

  • Practice, practice, practice. Write yourself sample business cases and have a friend pretend to be the interviewer. Pull out sample ones from books like “Case In Point” and see if you can identify frameworks and questions off the bat.
  • Learn the frameworks. Make acronyms. I used CPCC frequently to think about “Customer, Product, Competition, Company”. It came together in my head relatively easily during business situations.
  • Stay composed, friendly, and energetic. If you get nervous or panic in a 30 minute case interview, it might constitute a red flag.
  • Engage the interviewer in conversation. If the interviewer is left in the dust while you are progressing on your case, they might begin to only imagine in their head what you’re thinking.
  • I can’t litigate how each company does their cases without spilling trade secrets. Check glassdoor or guess :-)

I felt compelled to write this all out after writing it separately in various emails. If you’d like any more information on advanced cases, reach out. Good luck and god speed!

Kushaan is an IBM Consultant based out of Washington D.C. His interests are rooted in strategy consulting, entrepreneurship, social media, and the intersection of technology with social impact. He enjoys blogging about life, career insights, social technology, and hacking the corporate environment. If you liked this post, follow him on twitter: or click “Follow” at the top for more posts on Linkedin.

Growth @Livongo • Bostonian • Fan of sports and quirky theatre • Marketing Nerd • Weekly reads ✍️