Logic trees... are they necessary?

Structure
New answer on Jan 09, 2021
9 Answers
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Anonymous A asked on Jan 02, 2021

Hello!

I wanted to ask the community's opinion about logic trees... is it truly necessary to fit your thoughts/approach into this structure?

I have been prepping cases for over a year now, and have never fully adopted the logic tree as the way to structure my approach. I find myself using it for more basic profitability cases, but group my approach into more conceptual buckets or process-driven structures for all other cases.

I'm curious to hear from any "real-life" consultants out there -- Are logic trees a key tool to use when you approach new projects? Are they used on the job frequently? Also, in terms of case interviews -- does failing to adopt the ability to "think in logic trees" potentially hurt one's performance?

Curious and grateful to hear your perspectives,

M

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Adi
CoachingPlus Expert
Content Creator
replied on Jan 03, 2021
Accenture, Deloitte | Precision Case Prep | Experienced Interviewer & Career Coach | 15 years professional experience

Logic trees are important but are not the gospel anymore. With agile, design thinking and digital approaches, traditional methods of problem solving are being challenged.

That being said, for purposes of case interviews get comfortable with logic trees and use them as required. Any such tool must be used to give you a head start. Dont get bogged down by it and be bold to chuck it and use something of you own (obviosuly buidling on structures/frameworks you have learnt)- this will also make your solution and approach a bit unique for the interviewer.

Another way to analyse a problem within a company can be as follows. Any company that operates in any industry will have following layers:

  • Customers they sell to (B2B or B2C)
  • Channels to sell to those customer (e.g. retail, online etc)
  • Product & Service to sell through those channels to the customer
  • All underlying processes
  • Data to enable the processes
  • Technology/Tools to execute the processes
  • People & Organisation
  • Physical assets (offices, warehouse, stock etc)
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Henning
Expert
updated an answer on Jan 02, 2021
Bain | passed >15 MBB interviews as a candidate

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)

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Ian
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Content Creator
replied on Jan 02, 2021
BCG | 100% personal interview success rate (8/8) and 95% candidate success rate | Personalized interview prep

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.

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Vlad
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replied on Jan 04, 2021
McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School

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

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Ken
Expert
replied on Jan 03, 2021
Ex-McKinsey London final round interviewer

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.

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Clara
Expert
Content Creator
replied on Jan 04, 2021
McKinsey | Awarded professor at Master in Management @ IE | MBA at MIT |+180 students coached | Integrated FIT Guide aut

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

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Gaurav
Expert
Content Creator
replied on Jan 04, 2021
Ex-Mckinsey|Certified Career Coach |Placed 500+ candidates at MBB & other consultancies

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

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Antonello
Expert
Content Creator
replied on Jan 04, 2021
McKinsey | MBA professor for consulting interviews

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

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Iman
Expert
replied on Jan 09, 2021
BCG | Strategy& |Roland Berger | Interviewed >100 candidates in formal hiring process

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

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Adi gave the best answer

Adi

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Accenture, Deloitte | Precision Case Prep | Experienced Interviewer & Career Coach | 15 years professional experience
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