Practicing Problem Structuring in Case Interviews


Firstly, I would like to sincerely thank you for the all the great material you've published to help with case study interviews.

I have recently purchased the LOMS programme and I would personally recommend it to people who are serious about entering consulting. However I just have a few questions.

I understand that the interviewee should approach the case trying to form a hypothesis and go about capturing data which will help either prove (dig deeper) or disprove (move logically onto another branch) the hypothesis. But I'm currently struggling with forming hypotheses and figuring out what data I need to determine whether the hypothesis is true. Do you have any advice on methods to sharpen this skill?

I have memorised your case frameworks, but when I enter a framework, I continually ask myself, "What's my hypothesis?" I obtain a hypothesis but nowhere near as crisply and quickly as the candidates featured on the LOMS programme, I'm much slower.

But I find it more difficult once forming that hypothesis; what data do I need to prove or disprove it? Are there any ways you can help this thought process?

I completed my PhD a few years ago and have some industrial experience in Operational Improvement. I currently have an Interview with the [specialized division] team in Mckinsey [European city]. I'm spending as much time as I can polishing my maths and case interview practice (your maths drills are great!!!!!!!).

Do all Mckinsey offices give cases (strategy case interviews that I'm currently preparing for) or do the cases for specialist hires tend to be more specific for specialist offices and for experienced hires?

I'm nearly through this audio programme once already. Only 10 more times to run through this programme.

Really admire your commitment to helping potential consultants and if there's anyway I could help please don't hesitate to ask! Thanks again, Victor.


My Reply:

At this stage, I think you need to practice the process of setting a hypothesis and devising an issue tree that would test it.  It is okay that you're slow at the process now... as long as you understand the process. For better proficiency and speed, you just need to practice.

You can force yourself to use the process every day for everyday decisions. Should I eat in tonight or go out to dinner? What's your hypothesis and how would you test it?

You don't actually need to go through the data gathering steps, but instead just practice structuring the problem or "setting up" the structure.

Try to do it three or four times a day.

Should you take the highway or the local roads to your destination?

Should you eat vanilla ice cream or chocolate?

Should you bring an umbrella or leave it at home?

Have your friends or family ask you these kinds of questions and force you to set it up. Do it until you're completely sick of it, and if you were woken up in your sleep at 3am, you could form a hypothesis, structure it, and go back to sleep without even fully waking up to do it (not literally... but you get the idea).  This will help you to ace the case.

As for the specialist cases, I'm less familiar with them. My best guess is they will be on a wider range of topics -- not necessarily strategy. So the most common strategy frameworks of mine that you're most familiar with are less likely to apply. More likely would be the underlying ability to create a hypothesis and custom issue tree needed to test that specific hypothesis.

Practicing your problem structuring for everyday life decisions will help you immensely in this regard... as obviously there is no standard framework for whether or not you should choose vanilla ice cream versus chocolate.

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2 comments… add one
  • polo Feb 22, 2012, 8:45 pm

    like it, you are the best mr cheng.

  • Anonymous May 2, 2015, 7:06 pm


    For the question : Should I eat in tonight or go out to dinner? What’s your hypothesis and how would you test it?

    Assuming my hypothesis is “Yes, i should eat in tonight”..I am not sure what is meant by “How would you test it ?

    Are these just questions i need to answer when deciding whether i should eat in or out ? So for example ..

    – Do i have the ingredients to cook ? – Yes

    – Can i cook ? – Yes

    – Will i potentially lose out on an opportunity
    to meet new friends if i did go out ? – Yes

    – Is meeting new friends important for me ? – Yes

    So maybe it makes sense if i did go out.

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