One invisible mistake torpedoes your problem-solving
Implicit assumptions are simple but damaging mistakes. The hardest part is that they are invisible to consultants. In this post, I provide one example and an exercise to practice spotting them.
Have you ever been caught off guard by a partner’s question?
Imagine you bring a perfect slide to a partner. One question, and the whole thing crumbles. It’s extremely embarrassing. And damaging to your reputation.
Why does it happen?
Most likely, you make implicit assumptions.
A single implicit assumption can torpedo your whole problem-solving effort, often rendering your outputs absolutely useless.
What are implicit assumptions?
It’s the assumption you make in your argument that you don’t even know you are making.
And the hardest part is you don't see them.
Enough theory, let’s use one example to illustrate this point.
Here is a challenge for you. I give you a simple statement. Find an implicit assumption here.
A consumer goods company discovers that its top 10% of customers generate 55% of revenue. The marketing team proposes shifting 70% of the Ad budget from broad awareness to targeted retention for the high-value customers.
Does this look alright to you? Makes sense?
PAUSE HERE. THINK CAREFULLY…
What is the key implicit assumption here?
The key assumption here is that the top 10% group is self-sustaining.
But think for a minute, what if it is not true?
Where did those high-value customers come from? They most likely entered as new customers through the very broad awareness campaigns you are now cutting.
Kill the top of the funnel, and the bottom dries up within 18 months.
Imagine the partner catching this. That would be quite embarrassing.
At McKinsey, I saw this all the time.
Confident, data-backed recommendations built on assumptions nobody questioned.
And then a partner asks one question, and the whole thing crumbles.
This is what separates good consultants from great ones. Not sharper math. No better slides. The ability to see what the argument is silently assuming.
This is where critical thinking is absolutely important.
Unfortunately, it’s not being taught in consulting, although I would argue it’s the most fundamental layer of your problem-solving. If you make mistakes at this layer, your problem-solving will be super weak.
Partners spot these things pretty easily because they have tons of experience and sharp pattern recognition. But you don't have that yet.
What can you do to compensate?
You can learn and practice it.
For this reason, I built an interactive exercise for MBB consultants to practice spotting implicit assumptions and strengthen their critical thinking.
If you are an MBB consultant and want to improve your performance through personalized coaching support:
We will discuss your pain points, challenges, and aspirations. It’s a no-commitment call, just straight answers to your biggest questions.
If you want to learn more about my coaching program, read this post: The coaching program for MBB consultants.