MECE: 3 secrets for the perfect framework

MECE, pronounced "me see", is a concept commonly used at top consulting firms to talk about the approach consultants use to solve problems. Partners at McKinsey, BCG or Bain will often tell their team "I looked at what you've done. I like it but can we make this framework MECE?" 

MECE stands for Mutually Exclusive and Collectively Exhaustive. Consultants usually solve clients' problems using a framework. For a framework to be MECE, its different parts CANNOT overlap (Mutually Exclusive). But they need to cover ALL possible causes of the client's problem (Collectively Exhaustive).

This is an important concept if you are preparing for case interviews as your interviewer will expect you to be aware of it. So let's cover the following three topics in this article (click to jump to the relevant section):

  1. MECE definition and importance
  2. Three simple ways to make your framework MECE
  3. How MECE do you have to be to get an offer?
1. MECE definition and importance

MECE definition and illustration

Mutually exclusive

The first characteristic of a MECE framework is that its different parts are mutually exclusive. In other words, there is NO OVERLAP between them. Let's imagine for a second that we are helping Coca-cola identify the root-cause of a profit issue they are experiencing. 

Here is an example a framework that's NOT mutually exclusive:

  • Profits in US market
  • Profits for Coke, Diet Coke and Coke Zero products

This approach is not mutually exclusive because there is an OVERLAP between the two different areas of the framework. While looking at profits in the US market, we will already analyse profits for Coke, Diet Coke and Coke Zero products. There is duplication of work across the two branches.

And here is an example of a framework that's mutually exclusive:

  • Profits in the US market
  • Profits in the European market

This approach is mutually exclusive because each branch in your framework corresponds to a geographical area. And there is no overlap between the different geographical areas we have chosen.

Collectively exhaustive

The second characteristic of a MECE framework is that its different parts are collectively exhaustive. In other words, they cover ALL POSSIBLE CAUSES of your client's problem. Again, let's image that we are helping Coca-cola get to the bottom of a profits issue.

The framework we have used previously is actually NOT collectively exhaustive:

  • Profits in the US market
  • Profits in the European market

Why? Because Coca-cola sells its products in other countries than the US and European markets. If we only look at the US and Europe, we might miss the root-cause of the profits issue which could come from another country. To make this framework MECE, we need to list all the geographies where the company sells its products:

  • Profits in the US market
  • Profits in the European markets
  • Profits in the Asian markets
  • Profits in other countries

Note that it is common to have an "Other" category in frameworks to make sure that they are MECE. This is a technique you should feel free to use in your interviews.

Why it's important?

So why is everyone in consulting obsessed with making things MECE? The answer is actually quite simple: being MECE is client-friendly.

There are three main benefits to MECE structures that clients love:

  1. Clean and intuitive. The first benefit is that the MECE principle forces you to create frameworks that are clean and intuitive. There is no overlap between the different parts which means it's easy for clients to focus and discuss one element at a time. You're never mixing apples and oranges.
  2. No risk to miss something. The second benefit is that if your framework is MECE you can't miss any causes of the issue your client is experiencing because you will cover EVERYTHING. Clients are often worried that you will "miss something" and being MECE reassures them. 
  3. No duplication of work. Finally, taking a MECE approach enables you to make sure that there's no duplication of work in your consulting project. It means that John can cover the US market, Julie can focus on Europe, Mike on Asia, etc. Your team can organise itself in a clear and transparent way which once again clients appreciate.
2. Three simple ways to make your frameworks MECE

Now that you know what MECE means and why it's important let's turn our attention to three simple tips you can use to make your own frameworks MECE. 

#1: Use a maths formula

The first tip is that using a maths formula can work really well to break down a framework in a MECE way. This is because maths formulas are MECE by nature. Let's go back to the Coca-cola profits example for a second. We know that Profits = Revenue - Costs. And we can use that formula to structure our framework:

  • Revenue
    • Units sold
    • Price per unit
  • Costs
    • Fixed cost
    • Variable cost

You will have probably recognised the profitability framework above. But profitability cases are not the only ones where you can use the maths formula approach. In our experience, it works really well for any kind of case where you are either estimating a number (e.g.: market sizing questions) or you are looking for the root-cause of a financial problem (e.g.: revenue decline, cost increase, etc.)

#2: Use a supply-chain / process

In some cases, structuring your framework using a supply-chain or a process also works very well. Each step in the process is separate so your framework will be mutually exclusive. And if you cover ALL the steps of the process your framework should also be collectively exhaustive. Let's apply this approach to the Coca-cola supply-chain as an example:

  • Sourcing of raw ingredients
  • Manufacturing of Coke concentrate
  • Shipping to local markets
  • Mixing and bottling of Coke in local markets
  • Distribution to retail points (e.g.: stores, wholesalers, etc.)

In our experience this approach works really well for operations and supply-chain case interviews. If you are unsure of the the supply-chain of the company you can still use this approach by asking clarification questions to your interviewer at the beginning of the case.

For instance here you could have said something like: "I assume Coca-cola manufactures its products in the different countries where it sells. Is that correct?" And your interview would have replied: "Coca-cola actually has two types of plants. They've got two or three Coke concentrate plants per continent. And the concentrate is then sent to local markets where it's mixed with water and bottled." This information would have enabled you to put the framework above together.

#3: Use common lists

Finally, the last approach you can use to make your framework MECE is to rely on common lists of elements that are important in business and often come up in case interviews. Here are a few examples applied to Coca-cola. Each bullet point could be a different framework:

  • Products: Coke, Diet Coke, Coke Zero, Other
  • Countries: US, Europe, China, India, Other
  • Business entities: Suppliers, Clients, Competitors, Regulator, Company itself
  • Distribution channels: Retail stores (e.g.: Walmart), Restaurants (e.g.: McDonalds), Wholesalers, Other
  • Etc.

Being familiar with these lists can be a big advantage in your interviews. We would encourage you to learn the bullet points above and to enrich the list as you do more and more cases.

3. How MECE do you have to be to get an offer?

Now that you know 3 simple ways to make your frameworks more MECE let's discuss how important this is for your consulting interviews. This is subject to much debate. Some people will tell you that your framework MUST be MECE to have a chance to get an offer. But in our experience, this is an exaggeration.

Our opinion is that it's much more important to be RELEVANT than to be MECE. If your framework is MECE but it is not adapted to solving the case at hand you will not get an offer. However, if your framework touches on the right elements to solve the client's problem but is not perfectly MECE you still have a good chance of getting an offer.

In reality, consultants are not always MECE. In fact, if you analyse consulting frameworks, you could argue that some of them are not completely MECE. The 3Cs is a good example: Customer, Company and Competitors. What about suppliers and the regulator? Aren't they relevant?

In some cases suppliers and the regulator will be important, and competitors won't. In others, using the 3Cs framework as-is will be the right thing to do. Once again, it's all about being RELEVANT and solving the client's problem.

In our McKinsey Case Interview Prep Programme and BCG & Bain Case Interview Prep Programme, we teach a simple step-by-step method to create bespoke frameworks for each case. This approach focused on being relevant first, and MECE second. If you would like to get a taste of it, you can watch the video extracts below or download our Free Case Prep materials here.

Conclusion

MECE frameworks are great because they are intuitive and comprehensive which makes it easy for clients to understand what you are doing. As a consequence, you should be aware of what MECE means and you should apply the three simple tips we've given you above in your case interviews.

However, you should not be too obsessed about always being MECE. In our experience, it is much more effective to focus on being relevant and on solving the client's problem first. And to then step back and fine-tune your framework to be as MECE as possible.

What's your opinion?

What's your opinion? Do you think all frameworks should be MECE? Or do you agree with us that being relevant is more important than being MECE? Let us know below and our team will answer any thoughts or comments you may have.

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