26 Interview Questions the Top 10 Consulting Firms Ask

The key to any good interview is preparation—and there's no better preparation than knowing the kinds of questions that you're likely to face. With that in mind, I took a look through the thousands of responses from our 2013 consulting survey and selected some of the most representative questions that successful candidates had to navigate. For this post, I limited my research to questions from firms that made the top 10 in the Vault Consulting 50 this year—in a follow-up, I'll focus on questions from different types of firms: boutiques, firms with particular practice area specialties, and so on. In the meantime, feel free to test out your answers to any of the below—or to provide feedback on others' answers—in the comments.

Situational & Personal Questions 

These are the standard questions that almost every professional in any walk of life will have to negotiate successfully if they're to find themselves getting a job offer. However, just because they're not specific to the consulting industry doesn't mean that you should take them lightly—tripping up on a question about your long-term career goals can do your application just as much harm as blowing the case interview portion. Some examples: 

1. "Please describe your most important leadership experience and the impact that you had as a leader."
2. "Describe a problem that you would like to tackle at [this firm], why and how would you pursue it."
3. "If I were to speak to your colleagues from your most recent internship (or friends in school), what would they say about you? What are the strengths and weaknesses they would share?"
4. "Describe a situation where you failed. What did you learn about yourself and how did you change as a result?"
5. "Why our firm instead of your current firm? What do you know about us compared to your firm?"
6. "Tell me about a project that didn't go well and why and what you would do differently next time?"
7. "How do you quantify a lead?"
8. "Can you describe your brand?"
9. "How have you dealt with low team morale in the past? Provide an example of when you had to give a bad performance review."
10. "Describe a project which challenged you. Describe a client relationship which was challenging."        

Market Sizing/ Estimates 

Market sizing and estimation is a crucial skill in the consulting world, and is also something that is conveniently easy to test for in interviews. In fact, every single firm in the top 10—and a clear majority of the firms we survey every year—ask candidates to estimate the size of something, whether it's ice cream cones sold in Beijing in a day, or the potential market for electric cars in the United States. Regardless of what you're asked to figure out, you should always start by explaining your assumptions—population size, percentage of the population likely to use said product (and why you've settled on that percentage), and any other factors that are likely to have a significant effect on the estimate. Indeed, showing that you can logically approach the problem is far more important than whatever number you might eventually arrive at, so be sure to do the bulk of your reasoning out loud, and make the process a conversation with the interviewer, so that they can follow your thought process. 

Here are some sample market sizing questions from this year's survey: 

1. "How many airplanes leave from Boston's Logan Airport on Monday?"
2. "How many lightbulbs are there in Manhattan?"
3. "What is the market size for a cancer diagnostic technology in the U.S.?"
4. "How many passengers fly through LAX in a calendar year?"

Case Questions 

No consulting interview would be complete without case interview questions that test a candidate's ability to think strategically about problems. Answering them is all about preparation (that's why you're at business school—and why there's no shortage of guides to help prepare) as well as a continuation of the approach for market sizing questions—make it a conversation, and explain every step of your thinking/process along the way. Again: showing that you can arrive at a solution after thoughtful questioning and analysis is far more important in these questions than being able to throw out a brilliant new strategy on the fly, so focus on the process, and allow it to lead you to a solution.  Some examples:

1. "Client X is deciding how best to enter a new market. They have a choice of buying an existing company, or developing the technology in-house. How would you think about advising them to make the best decision?"
2. "How should a nuclear plant deal with waste products?"(Hint: the same person who submitted this question told us that the answer "involves heavy analytic calculation about the recycling of plutonium, various storage option with different cost structures, and recommendations taking into account various green initiatives and business risks.")
3. "An online brokerage is growing well but can't seem to reach their profitability goals; what could be going on?"
4. "You're discussing a contemplated divestiture with the CFO of a large corporation. What are some of the points you'd want to make in considering how our firm can potentially assist him or her? What key themes would you want to hit on?"
5. "Your client is a Fortune 50 aerospace and defense company interested in entering adjacent markets through organic or inorganic expansion. Which markets should she enter and how?"
6. "How would you go about advising a hypothetical client on commercializing a teleportation device that they have invented?"
7. "Should I open Chick-Fil-A on Sunday?"
8. "Should I put Wi-Fi on my airline?"
9. "Our client is thinking of acquiring a company that makes a certain type of medical device; what do they need to consider in making their decision?"
10. "Our client wants to enter the wine market; how should they go about doing so?"

Brainteasers/ Random Knowledge 

While it's now rare for consulting firms to ask the "golf balls in a 747"-type questions that were in vogue a few years ago, there are occasional interviewers who like to stretch candidates to see how they perform under pressure. Here are a couple of questions that stood out in this category.

1. "You are sitting on a camel on the edge of the Sahara desert. How far can you see?"
2. "Who is Sancho Panza?"

Related:

For examples of interview questions from specific consulting firms, check out the profiles of the firms in our consulting rankings by clicking the firm's name in the rankings.