Yes, logic trees are absolutely essential in both case interviews and actual cases.

When developing a framework for a case interview, using a logic tree is essential to get to a MECE appraoch. The question you need to ask yourself is "What sub-questions do I need to answer, so that I can roll up the answer and give a recommendation for the entire case?".

Structuring your framework around process is not a good idea, because that will not result in a MECE structure. The temptation to jump between the content topics is usually too high to be manageable and you're delivery will become a mess.

And also during your work as a consultant logics trees (or driver trees as we call them at Bain) are a key tool that you'll deploy in every single case you're working on. I don't think I've worked on a single case in which we did not deconstruct the main hypothesis into smaller chunks that can be solved separately. - BTW this is another reason to use driver trees in case interviews, although a more conceptual one: As process-driven frameworks don't really allow to split the work between different team members, they shouldn't be used in actual cases - and as a simlation of that in an interview situation.

So to answer your questions: Yes, it's a critical tool, and yes, it will hurt your performance in the interview if you're not applying it properly.

(edited)

Hi there,

They absolutey are used heavily in consulting!

That said, a variety of tools/ways of thinking are also used. You may not always use logic trees or root-cause analysis structures. In some cases, you may just need to have a series of buckets without a substructure (i.e. we need to improve people, processes, and tools).

That said, regardless of the exact approach, for every project you absolutely have to segment, organize, and structure your thinking into digestible chunks/themes.

Hi,

Logic trees is just one if the way to structure things among others. It's up to you what type of structures (or a mix of different types) you use on different levels of the case:

• Math (logic trees, e.g. profitability)
• Drivers
• Strategic buckets
• Frameworks
• Value chain / customer journey
• Segmentations
• Project plan

Best

I feel there may be a slightly different nuance by firm and individual interviewers. My personal experience having been a McKinsey final round interviewer is that they are not a must. I have extended offers to numerous candiates who never explicitly drew out a issue/logic tree. What I would be looking for is the candidates ability to break down a problem into its component drivers which many strong candidates do more inherently. What you mentioned as "conceptual buckets or process-driven strucutures" to me still sounds like a way of breaking down a problem even if it isn't expliclity a tree. The more important factor is whether your structuring is relevant and has sufficient depth to be actionable.

Hello!

This is something I used to wonder too when I joined McKinsey :)

You do use them, sometimes. Particularly at the beggining of an engagement or when new problems are fist thought about.

However, reality is much more complex than mock cases, hence you also use other tools and problem solving techniques.

Best regards,

Clara

Hi M,

Logic trees are not necessary, but they can be useful and it won't hurt to know how to use them. In any case, if you're able to solve a case with a different approach and you obtain the result, it really doesn't matter how you got there.

Hope it helps,

Cheers,

GB

Hi,

They are really useful for solving cases and they are actually used in consulting.

They'll become natural to you once you've done some good cases with good partners.

I agree with you that sometimes other approaches are better than a logic tree (even if you could look at a case almost always in terms of logic trees).

If you don't use one, it won't impact your performance if you solve the case correctly and in a structured manner.

Hope this helps.

Best,

Antonello

Hi,

Logic tree is a useful tool to get your thinking in the right order it is used also in real life. However, as we are hypothesis driven along the way of the project there will be changes / adaptation to the logic tree as we discover more insights.

Relating this to a case interveiw, a logic tree will make it easier for the interviewer to follow your thinking (very important) and along the case you can make adjustments as you discover new insights from the discussions.

Best,
Iman