How to Use the MECE Principle to Find the Root Cause of Problems

Applying top consulting frameworks to break down big questions.

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Problem-solving in most companies is a mess.

Discussions mix up cause analysis with solutions. As-is observations with to-be.

The loudest people are heard. And/or the highest paid.

Time is lost in various iterations that could have been reduced to 1-2 meetings.

How do we get out of this chaos?

By using structure.

Think of the following example:

We examined why an airline’s fuel cost had increased in one case.

So let’s break it down.

What is the total cost of fuel equal to?

Well, it’s the total distance flown multiplied by the cost for each kilometer (km), isn’t it?

So, the root cause could be an increase in distance covered or an increase in fuel cost per km.

Ok, let’s dig deeper.

Why might the total distance flown have increased?

→ Mathematically, it’s the number of trips multiplied by the average distance per trip.

Why might the fuel costs per km flown have increased?

Again, mathematically, it’s the amount of fuel (liters) times the cost per liter.

Typically # of trips and average distance is data that we have easily available.

Here, we could break it down into:

  • New destinations added

  • The frequency of flights to existing destinations has increased

Why may the average distance have increased?

This could be due to alternative routes that we had to take over some distances, e.g., for political reasons.

That’s a good starting point.

But what about the amount of fuel consumed per flight? Why would that increase?

Here, we dissected it using the “opposite word” framework.

  • The aircraft mix has not changed, i.e., our existing planes, for some reason, consume more than before. This could be due to increased average weight on the planes, changes in maintenance, or flight behavior.

  • The aircraft mix has changed, and bigger planes may consume more.

There we go.

That is a solid starting point for finding out what happened.

We can precisely target each branch. By the time we met again, we had all the data.

Based on this, you can start talking about solutions.

Note how we combined different breakdown frameworks.

We started with a mathematical breakdown and then used the opposite word structure, as indicated by the darker blue. Finally, we used a conventional framework, i.e., logic, in the dark blue.

As Einstein said:

If I had an hour to solve a problem, I’d spend 55 minutes thinking about the problem and 5 minutes thinking about solutions

Do you have any tough topics to crack? Let me know.

Talk soon,


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