Consulting Case Study Interviews

You will perform better if you are familiar with case study formats and expectations, and have invested time to practice many different examples. Seek out ways to learn and practice:

• Start by reading some of the books listed in "Our Resources" below and looking at the web-based resources.
• Use the 'virtual internships' available from leading firms on The Forage website to work through some extended management consulting case study materials. These will be more in-depth than a Case Interview but provide highly relevant learning materials and content to help you understand the range and style of issues you may be asked to address.  
• Use examples provided by management consulting firms on their recruitment webpages. Many include example case questions (and worked answers) that you can work through, and short videos are now common.
• During term, look for employer-led case study workshops advertised on CareerConnect: usually the Careers Service hosts three workshops in Michaelmas term, two or more in Hilary term and a further workshop in Trinity term.
• In addition, employers host their own case events across Oxford in Michaelmas term, details of which will be advertised on their own recruitment webpages.
• Join business or consultancy focused student societies as listed in our Management Consulting Societies resource.

Attending one or two workshops will help you to get started, but it is important to practice more, and to work with others to practice case studies face-to-face. This will help you to get used to:

• thinking aloud;
• showing how your ideas are developing;
• stating the assumptions or constraints you are applying to your thinking; and
• getting used to reviewing and revising the ideas that you have developed in front of someone else.

It is best to partner with other students to practice. Aim to play the role of 'interviewer' as well as 'interviewee' as you will learn different things from having to watch and listening to others. For example, you can learn the value of a quickly sketched graph or flowchart to support an explanation, or identify the critical information needed to explain a new concept or proposal clearly.

Working with a number of different partners can also be invaluable. Even within a single organisation you will meet many interviewers, who each work in a different way. Modelling this variety in your practice will help as it will expose you to differing work styles and broadens the variety of concepts you are likely to encounter and be comfortable using in your own analyses.

Some student societies run sessions where students work with other students to practice, and may offer a Case Buddy Scheme scheme like the one offered by CapitOx in recent years. Details can be found on their website or contact the society's president for more information.

See the "resources" sections below for materials to get your started and ways you can get practice.

• Clarify. You’ll need to understand the problem and its component parts sufficiently to get started. Only if absolutely necessary should you seek extra information or clarification. It’s a good idea to briefly state your understanding of the problem in your own words. The case may appear simple and with no data (for example, ‘What would you think about in setting up a new coffee shop in Oxford?’) or very complex with pages of printed charts and graphs. It is much better to make assumptions (aloud) and get started, such as, ‘We are looking at burger sales in Europe; this is a large market so I propose to focus first on England and then extrapolate the results’.
• Take the lead. The interviewer wants to see if they’d like you on their team so show them that you can take the initiative.
• Think out loud. The interviewer wants and needs to know what you are thinking. They are not telepathic so describe out loud what you are thinking every step of the way. However, think before you speak, so the thoughts that you do share demonstrate your judgement.
• Write things down. Make sure you have an A4 pad of paper and pen/pencil with you, on the slim chance they don’t supply them. As you think and talk, write large and legibly, in note form so the interviewer can follow what you are doing and perhaps join in. Leave lots of space so you can add new thoughts as the case develops. Don’t be afraid to start new sheets and draw pictures/sketch graphs/block diagrams.
• Landscape paper. We recommend that you use the paper in a landscape orientation. You can move left to right across the page(s) with Structure –> Hypotheses –> Data –> Recommendations, which will mirror how consultants’ presentations appear. You may well need more than one sheet.
• State your approach. It’s not so much the answer you get but the process you use to get there. Avoid the temptation to answer the case immediately with a possible solution – consultants have to show they have been thorough and demonstrate how they have explored every option. In the jargon it’s ‘MECE’ (pronounced “meesee”): Mutually Exclusive and Collectively Exhaustive.
• Explain. Once you are clear about the problem, explain how you are going to approach it. List some top-level topics either down the left hand side of the (landscape) page working towards the right hand side with more details, or, work from top to bottom (portrait). Either way, the key is to clearly show your thinking.
• Ask. After you have laid out the structure and demonstrated that you can take the lead on the problem, ask if the interviewer wants you to focus on a specific area or has more information for you. This can be a full three to five minutes after you start; don’t be tempted to ask for help sooner as that shows you need lots of guidance and would be interpreted as someone who does not take initiative and would not pull their weight on the interviewer’s team.
• Listen. Be ready to listen and respond to any direction that your interviewer may give you in response to your proposed analysis. The structure you recorded on paper will help you to remain focused and provide you with a ’map’ or reference point if you get diverted or distracted. Also, if/when you think of topics you missed, you can add them to your structure. Most importantly it will demonstrate to the interviewer that you have the logical thinking and analytical skills they seek.
• Develop hypotheses. Don’t try to answer the question directly but develop hypotheses to which you may not have the answer, for example,  ‘prices are higher than competitors’ and ‘revenues have dropped because volume has dropped’. Keep talking as you develop all this.
• Suggest data you would need to prove/disprove the hypotheses. Sketch some simple charts, for example, ‘I’d need to know sales of car tyres over the last three years,’ then draw an x-y chart, with time along the x axis and sales up the y axis. Then guess some lines, for example, sales rising over the three years. You don’t have to know the actual data (how could you?) but you can say, ‘If sales have done this, then…’.
• Develop some recommendations. Once you have found/agreed some data, it’s time to move to the final stage, recommendations for the client. ‘If I were working with a client considering opening a new coffee shop in Oxford, based on these data, I would recommend…’.
• Be comfortable working with numbers! If you have not used them for a while, make sure you are especially comfortable with percentages, ratios, long division and multiplication, estimates, and working with large numbers. Dust off your mental arithmetic skills. Be happy to round to one or two significant figures. Make sure you know some rough data, such as populations of UK (+/- 60 million), London (+/- 8 million), EU - pre-Brexit (+/-500 million), USA (+/- 300 million); size of a football field (+/- 7,000m²) or length of a jumbo jet (+/- 70m); weight of a human (+/-70kg). It is also a good idea to use the metric system since it’s easier not to get jumbled up with units.
• Use your common sense. You may not have any business experience in the areas that the case study covers, so instead make use of any perspectives that you may have acquired from being either a user or a consumer of the products and services that are the subjects.
• Be ready and willing. Be prepared to respond to further interviewer requests as you go along, e.g. to brainstorm ideas or to work through some estimates of market size. Positive energy, engagement and enthusiasm (perhaps even enjoyment!) are important indicators that you are more likely to thrive in a consulting career.

Remember, case studies are a skillset, not a script. Go in with the mindset that something might surprise you. With careful preparation, and following the framework above, you can increase your chance of successfully navigating case study interviews with confidence.

Frameworks

In your research and reading you are likely to come across analytical frameworks that can to help you deal with some of the cases you will face. Some of the basic frameworks include:

• SWOT analysis: strengths, weaknesses, opportunities, threats
• 4 Cs: customers, costs, capabilities (of the organisation), competition
• 7 Ps of Marketing: product, price, promotion, place, packaging, positioning and people.
• Porters five forces

If your degree studies have no business element, the interviewer will not expect much sophistication and will probably help you to choose useful factors to focus on. It is important, though, to show a degree of commercial awareness by understanding some of the main terminology that you may hear or face in a business context, e.g.: Profit or Loss = Revenue – Costs.

There are essentially two types of business cases that you can prepare for:

1. 'Profits are down'. This is an historical view and we suggest you start with breaking down the elements of profit and then probe each one. Make sure you are familiar with a basic profit and loss account: check out our basic definitions of profit and loss terms for an example below.
2. 'Market entry'. This is a future focused view and can arise from an organisation wanting to enter a new market (for example, a new country), or adding a new product line (for example. adding an electric or hybrid vehicle to a range of cars), or both. You could use the 'Seven Ps' framework for this one.

Bear in mind that a case study could start as a ‘profits are down’ case and turn into a ‘market entry’ case, for example:

“So, having identified the source of poor profits, we can explore ways to improve matters by adding new markets”.

Generally speaking, for most non-MBA graduates, recruiters are interested in assessing the quality of your thinking and your approach to the problem. Don’t try to be too clever or over-elaborate in how you approach a question.

Profit and loss terms

NB: The numbers above are all examples for a mythical, profitable business. There are several terms for the same heading e.g. “Margin” instead of “Profit”. What’s included in fixed and variable costs can vary depending on the industry and product. In a case study you’ll usually stop at Operating Profit.

You may also get two types of basic maths estimation questions: simple (in that there is only one way to answer it) and complex (there are many ways to get an answer). The simple type tests your comfort with handling numbers and making estimates. Examples include:

• How many footballs would fit in this building?
• How long would it take to move Mount Fuji?

The complex type of maths estimation tests your creativity in thinking about approaches; they are generally consumption related. An example might be: “Estimate how many petrol stations there are in London”. The best candidates will think of two or three ways to answer this question. The trick is to make simplifying estimates and assumptions, describe aloud the assumptions you are making, write things down, keep track of the sums, and don’t use a calculator. At the end, go back and identify where you have made assumptions and put some ranges on your original guesses, for example, “I guessed the population of London at 5 million, but if it is actually 8 million then I’d increase my answer by 60%" (that is (8-5)/5).

Although you may be working with rough estimates and assumptions, it will help you make a more confident start and ensure your estimates are based on sound assumptions if you:

• learn a few key numbers - for example, populations in major markets (e.g. UK, Europe and the USA) or cities (Beijing; Lagos; London; New York; Paris; Singapore); an idea of size or distances in USA, Europe, London-to-Sydney, the circumference of the earth at the Equator.
• can estimate some sizes of common objects, including an aeroplane, a building, a city, a car, a human being, a football, a golf ball.

As you read more and practice cases, you might jot down notes of numbers that you find yourself using more than once.

Books

You may be able to find copies of the following case study books through the University library or via student societies. Otherwise have a look at cheap copies with second-hand booksellers online or consider purchasing new with other students applying for consulting:

• Case In Point, Marc Cosentino
• Case Interviews: mastering the case interview, Alexander Chernev
• WetFeet Press Career Management Insider Guides: Ace Your Case!, Consulting Interviews / Ace Your Case II-V
• Management Consulting, Joe O'Mahoney
• the Vault (Career Library) Guide to Consulting
• Teach Yourself Successful Consulting, Anna Hipkiss

• Ace the Case - management consulting case interview questions
• CapitOx - CapitOx usually has a Case Study Buddy scheme to find and interact with students around Oxford who are also interested in consulting and want to practice case study interviews.
• Case Coach.com/blog information, advice and resources from Case Coach, a firm offering a Case Library with 100+ cases to practice. Requires registration.
• Case Interview Bootcamp -  An online bootcamp to help you prepare for your case study interviews.
• Case Maths - A tool to help you practice mental arithmetic.
• Case Questions
• Consulting Case 101 - a resource offering lots of cases by industry, by case type and by consulting firm and a Case Partner opportunity to practice with others in your area.
• Target Jobs: Management Consulting

Case resources from the firms:

• Bain & Company: Interview Preparation
• Kearney: Crack the Case
• LEK: Interview preparation
• Oliver Wyman: Interview preparation
• The Boston Consulting Group: Interview Resources
• McKinsey interview