Impress your interviewers: the case study

Why do consultancies use case study interviews?

Case studies test you in all manner of ways so they are one of the best – and fairest – methods of seeing a candidate ‘in action’. They are designed to evaluate how you process information, solve problems and react to new and surprising situations, as well as showing how you work within a team. Individuals or a small group of candidates are presented with a business problem and then given time to evaluate the information and brainstorm a solution. Case studies can be on almost any topic. 'The topic itself doesn't matter. No one expects you to know the market size for diapers in Southeast Asia offhand, for example,’ says Roland Berger. ‘But what is your approach? Can you estimate it? Educating yourself in basic data, such as average population sizes, will help prepare you for market estimation cases. Can you demonstrate common sense and make educated guesses?’ Oliver Wyman advises: ‘Think of the case interviewer as your client. Your interviewer wants you to solve the problem, and can help. Work together.’

What to do in advance

Read the firm’s graduate recruitment literature and check its website to see if it has sample case studies (the vast majority of consultancies do). Have a look at recent press releases to get a feel for the type of work it’s involved with as well as what industries it works across. Read the business pages of newspapers and imagine one of the businesses to be your client. How would you advise them? What would you base your recommendations on? What factors would you and your client need to consider before proceeding to the next step? Also check with your careers service as many run workshops and presentations on how to prepare successfully for case studies and assessment centres.

‘I practised with friends beforehand, so by the time I started interviews I was more comfortable with what to expect,’ says Olivia, an associate at The Boston Consulting Group, echoing the views of the graduates targetjobs has interviewed. The message is: practise, practise, practise.

Advice from consulting firms

Through our research of top consulting firms the targetjobs team has come across some valuable nuggets of advice for succeeding at case study interviews, such as:

• 'Sketch out a structure: your path to the solution. If you go astray, it will help you get back on track.' (Roland Berger)
• ‘Don’t panic if the answer is not apparent.’ (Boston Consulting Group)
• 'Pause periodically during the discussion to give your interviewer a chance to course-correct.' ( PwC )
• ‘If you need more data, ask for it. If you're stumped, take a creative leap.’ ( Oliver Wyman ).

Thinking out loud

The targetjobs team has been struck by a common thread – almost everyone we spoke to stressed that applicants should talk through their thought process with the interviewer. As L.E.K. Consulting puts it, ‘Formulate hypotheses – share your thought process as information is revealed.’ It’s a bit like making sure you show your calculations in a maths exam – it’s not enough just to come up with the answer. Given that case studies tend not to have ‘right’ or ‘wrong’ answers anyway, making your thinking process transparent is particularly important. ‘We do not expect candidates to actually solve the cases in interviews,’ says OC&C Strategy Consultants , Instead, the person interviewing you must be able to understand how you reach your conclusions – how you’ve broken the problem down, analyse information and structure conclusions.

If you're in a group...

If you’re working in a small group divide the tasks – you’ll get through them far quicker. There may be different personalities in your group and recruiters will be watching to see how you interact. They will also be looking for evidence of leadership and teamwork. Don’t dominate proceedings but do pitch in and contribute where appropriate. It’s important to be yourself rather than play to a type.

Expect the unexpected

Additional information may be sprung on you so be prepared. Interviewers will be looking to see how you deal with the unexpected as well as how flexible you are with processing last-minute information. Ask if you’re unsure about something. Asking clarifying questions such as ‘Does that make sense?’ to the interviewer, will ensure you’re on the right track and shows self-awareness.

Example case studies

We can’t tell you exactly which case study you’ll face, but we can give you a couple of examples of what it might be like:

Expanding a business

Your client is a global organisation that manufactures and distributes a wide range of chocolate products. They have two ideas to expand the business: either to introduce a new range through existing distribution channels or move into a completely new business, which will involve building a set of retail stores. To approach this, you will need to compare the returns of each of the different investments and decide which will be the better solution for the business. Make sure you can explain the reasoning behind your decision.

Increasing a supermarket's profitability

A supermarket chain has noticed a decline in its profitability. They have hired you to find out why this is and to recommend and implement a solution. You’ll need to work out why there is a decline in profitability – for example, is it specific sites or the entire chain’s performance that is suffering? Once you have identified the problems, work out a cost-effective solution that will allow the supermarket to address each in turn.