How to crack written case interviews

Florian Consulting Interview December 23, 2019 | 0

the image is the cover for an article on how to ace written case interviews

Written case interviews are a natural extension of the traditional case interview.
Bain & Company Recruiting

Many consulting firms employ written case interviews during their recruiting process, most notably BCG and Bain across several locations and offices.

How do I approach a written case interview?

We have compiled a tested strategy to help you effectively tackle this type of assessment. Below is our 6-step approach to written case interviews to focus your efforts, make sure you zero in on the crucial bits of the case, swiftly analyze and synthesize the available information, and provide a strong recommendation.

#1 Already have a plan when you go in for the written case

Since time is usually limited, you should have a plan on how long you want to spend on each task of the assignment beforehand. For a typical 60 minute case take

5 minutes for a quick scan of the documents
5 minutes to plan your approach (i.e. what do you need to figure out, what information is important, what analyses would you have to do, what output documents do you have to draft)
10 minutes to draft your output slides (doing this early helps you to focus your analytical efforts)
30 minutes to conduct analyses and work through the case
10 minutes to populate your slides with your findings and recommendations

For 30 minute cases, cut every step down by roughly 50%, so in total, you would need 5 minutes to scan the documents and draft a plan, spend 5 minutes to draft your desired output, then work 20-25 minutes on the material and use the last 5 minutes to populate your slides or flipchart.

#2 Focus – quickly separate crucial information from the noise

Written cases usually present you with an information overload that you need to sort out. First, figure out what information is crucial so you can conduct the necessary analyses to reach a recommendation. Write down what the actual question is that you need to solve right away and constantly relate back when you work on the written case. That way you should be able to read with a certain objective in mind and improve your comprehension speed. Second, dive into the relevant information, structure your analysis, and dive right in. Similar to a case interview, take a hypothesis-driven approach to frame your structure and thoughts. Synthesize each bit of your analysis to draw proper conclusions.

You can practice this by looking at business school cases, such as

HBS case studies
Ivey case studies
INSEAD case studies
MIT case studies (includes free materials)

Additionally, try to increase your reading speed with apps such as Spreeder, Reedy, or Read Me!

#3 Graphs and charts – interpret and distill key insights from graphs and charts

Written cases bombard you with charts, graphs, tables, and other visual depictions of data that you should use to test your hypotheses. Learn how to quickly read and interpret them.

What are the key messages and insights?
How does the information on several charts/ tables, etc. relate to each other?
What information is relevant to the case?

In order to prepare these skills, go through The Economist, the Wall Street Journal, or similar and use their graphs or tables to train your reading and interpretation skills. Alternatively, look at practice McKinsey Problem Solving Test or BCG potential test graphs. Time yourself while doing it, e.g. giving yourself 30 seconds before you are able to communicate what the graph is all about and what you would infer from it (what is the ‘so what’?).

#4 Math – quickly draft equations and conduct pen-and-paper math

Get into the habit of quickly setting up and simplifying calculations. Practice quick pen-and-paper math as well as estimations similar as you would do in a normal case interview. To prepare and practice, look into McKinsey PST, BCG potential test exercises as well as GMAT questions.

If you need to brush up on your math skills, we have created a program with detailed insider learning materials and close to 2,000 practice drills that mimick the McKinsey, BCG, and Bain case interview math for you here: the Case Interview Math Mastery.

#5 Storyline – draft a compelling storyline and tell it with visually appealing outputs

Create a top-down storyline of your recommendations. State your primary recommendation, then use supporting arguments to strengthen your position.

In practice, you would have one key slide talking about your finding and recommendation, i.e. the what or how the client should solve the problem, Then, you would have several supporting slides, discussing arguments for your solution, i.e. the why your approach is the best. Lastly, put a slide talking about the next steps to hedge your bets (what else would you like to know to make your recommendation even stronger) and demonstrate that you think ahead.

As for the slide design, use an action title on each, then some visual aid like a graph (remember to have a graph title as well) and some supporting bullet points, or if not applicable, just bullet points.

The action title should convey the so-what of your analysis. You need to show the implication of what you present rather than a description of what you have found.
The headings of each slide together should tell the full story. Everything below the heading is details of the story and should support your key message

#6 Presentation and defense – communicate and defend your recommendation top-down

If you have to present your findings at the end of the case, follow the top-down approach of your slide deck. Be confident and engaging when going through your recommendation and supporting arguments.

First present your headlines, e.g. “The client needs to cut cost by x% to break even within the next 5 years”; then move on to the details of the slide such as “Our manufacturing costs have increased by 25% over the last 3 years,..” This approach is very much like the recommendation you would give at the end of a normal case interview

Clarify when you are using hypotheses and assumptions that you were not able to verify.

Lastly, be open and ready to debate. The interviewers will definitely challenge your recommendation. It is important that you confidently stand your ground unless they make you aware of an obvious mistake on your part. In the latter case, demonstrate that you are coachable and save the situation by providing a plan of action on how to re-do the analysis to cross-check and improve your results.

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