Six Principles from Booz Allen Hamilton
Case Interviews: A Complete Guide

A typical case interview scenario opens with…. 

Interviewer: “John, the particular assignment I’d like to discuss with you involves helicopters. Our client is trying to decide whether the helicopter business is an attractive opportunity for continued investment. As part of the effort, they’ve asked us to specifically evaluate the demand outlook for non-military helicopters–30 years out into the future. Essentially, the client wants to understand the long-term attractiveness of the helicopter market. This product has roughly a 20-year life cycle, so you need to look out a long way. John, if you had to write the proposal for this engagement, how would you approach the work?”

Candidate: “All right (begins to babble) there are different kinds of helicopters, there’s an issue of geographic segmentation, it’s a form of air travel, it’s also for transporting freight and personnel . . .; so if we’re talking about 20 years, I wonder what the technology cycle is. . .”

PRINCIPLE ONE: Stay calm; take time to think. Use pauses to allow yourself time to think. You may want to jot down some points to help you think through the problem–a  whiteboard and/or pen and paper will be available to you in the interview room.

PRINCIPLE TWO: Begin by defining issues and hypotheses–NOT answers. Companies are not necessarily looking for the one right answer in the case. Instead, what they are looking for is how you think about a problem:

  • What are the issues you’re going to raise?
  • What hypotheses are you going to put together (i.e., potential answers for each issue that need to be supported or disproved by analysis)? For example, with the rapid expansion of many forms of electronic communication, fewer people will need to travel, including by helicopter. This is arguably creative as hypotheses go, but it could still be tested and supported or disapproved by data and analysis.
  • What are the questions that you are going to ask –to support or disprove your hypotheses? It’s the approach that they are looking for, not necessarily the answer, which is the second point to think about in preparing for the case: define issues, hypotheses, and then the questions to pursue.

PRINCIPLE THREE: Develop a framework: don’t generate random ideas. If you have an economic background, use it. Economic concepts make great frameworks. In building your framework, consider the classic business elements: Profit as the result of Revenue less Cost; Revenue as determined by Supply and Demand. This type of framework will help focus your questions. Never assume the interviewer knows where you are going, even if you have a framework in your head. If the framework has two elements to it, don’t start talking about one of them in detail without laying out the other orally.

PRINCIPLE FOUR: Surface potential causal, not descriptive, analysis. The interviewer will want to understand why things are happening, not just what has happened. Good consultants go far beyond the obvious, beyond basic market research. You need to decompose the underlying drivers of the situation–what’s actually making the situation change –now and in the future.

PRINCIPLE FIVE: Focus on the issues and opportunity facing the client. When you are doing the case, it is incredibly easy to get thrown off the track. Two great ways for tying back to the client’s position are thinking about the question that you’re answering and using the framework you’ve set up to guide you through the case.

PRINCIPLE SIX: Drive to potential actions for the client; be pragmatic. Thinking about issues, creating frameworks, and testing hypotheses are fun, essential, and at the heart of what we do. But the ultimate experience comes from using all this to help clients act. In the interview, think through the possible actions a client might take.

Source: Booz Allen and Hamilton