Consulting Case Study Interviews

For a management consulting job you are likely to have three to five interviews, of which two to four will probably involve a case study. The case study section of a one-to-one interview can last between 10 and 30 minutes, and you might even have two case studies within a half hour interview.

For a case study your interviewer will present a situation or question to explore and resolve either orally, or in writing, or both. For example:

  • How would you choose the optimal balance of economy/business class seats on an airline?
  • What strategy should a New World wine producer use when seeking to enter a European market?
  • How many washing machines are sold each year in the UK?

The question may be as brief as those above, may be a slightly more specific business problem explained to you verbally, or may require preparation by reading related documents right before the interview. Occasionally, the interviewer may ask you the business issues around something from your own background, so be prepared!

Case studies simulate aspects of consulting assignments and may even be based on a recent project led by the interviewer. Each case allows the recruiter to assess your capability and performance and you will need to perform well on a number of case studies to secure an offer of employment.

According to consulting companies, the key attribute they look for is passion. This translates into you needing to demonstrate engagement, energy, and interest in the problem under discussion as well as working through the question at hand. Remember, the interviewer is likely to be someone who manages consulting projects day-to-day (‘Job Manager’, ‘Engagement Manager’, ‘Senior Associate’) and so, as in all interviews, one of the judgements they will be making is whether or not you are someone they would want on their team.

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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 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 out loud;
  • 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 aloud. The interviewer wants to know what you are thinking. They are not telepathic so describe aloud what you are thinking every step of the way.
  • 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. Write large, legibly, in note form, and leave lots of space, so the interviewer can follow what you are doing and perhaps join in. Don’t be afraid to start new sheets (paper is cheap) and draw pictures/sketch graphs/block diagrams.
  • Landscape paper. It may be preferable to use the paper in a landscape orientation, since that is how consultants’ presentations appear. Another reason for using the paper landscape way round is you can move left to right with Structure –> Hypotheses –> Data –> Recommendations. 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.

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:

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

Heading

Example

Definition

Revenues

£500,000

Volume sold x price per unit, for each product line

Variable costs

£200,000

For example: raw materials, direct labour, direct advertising, royalties (these all vary based on the number of units sold)

Gross Profit

£300,000 or 60% (as a % of Revenues)

= Revenues – Variable costs

Fixed Costs

£250,000

For example: rent, rates, utilities, Selling, General and Administrative costs (SG&A) – these are all fixed and do not vary with the activity levels

Operating Profit

£50,000 or 10% (as a % of Revenues)

= Gross profit – Fixed costs

Non-operating costs

£30,000

For example: tax, Interest on loans, Dividends, Depreciation (i.e. the cost of writing off the expensive equipment the organisation has bought)

Net Profit

£20,000

= Operating Profit – Non-operating costs

 

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

The following books are available in our Resource Centre in 56 Banbury Road.

  • 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

Case resources from the firms:

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