McKinsey Interview - Choosing Relevant Buckets, While Being Creative

Hello, this is a great question and a common point of confusion for many candidates. Your ex-McKinsey mentor is absolutely correct: you did not need the third bucket.

The most important concept here is MECE. A partner wants to see you break a problem down into its most fundamental parts that don't overlap.

When a case explicitly asks how to fix a "decline in profits," the most logical way to do that is to look at the two things that make up profit: Revenues and Costs. That's it. Everything else you might look at is just a sub-part of one of those two.

Your third bucket, "Understanding the Decline," is a common mistake. It’s a diagnostic bucket, not a solution-oriented one. The insights you get from looking at customers or competitors will naturally lead you back to a revenue or cost issue. For example, if you find out a competitor is lowering their prices, that's a revenue problem. Including a separate bucket for it breaks the MECE rule because it's not truly separate from revenue.

You asked about being creative. The answer is yes, but your creativity should be shown within the structure.

At McKinsey, creativity isn't about inventing a new framework. It's about being incredibly specific and insightful within the one you're using. You can show this by getting very specific about what a bank's revenues and costs look like.

Instead of just saying "increase revenue," you could say "Let's look at revenues by breaking them into price (interest rates, fees) and volume (number of clients, number of transactions). For volume, we could explore cross-selling new products to existing clients."

This shows you can think creatively about the specific business while still staying within a perfectly logical and MECE structure.

Your approach was fundamentally correct, and the sample answer your mentor showed you was likely flawed in its structure. Trust your instinct to stick to the pure profitability framework for a problem like this. It is the most robust and professional way to solve it.

Hey there :)

For McKinsey interviews, especially final rounds with partners, what matters most from my experience is: clarity, logic, and tailoring to the exact question. A few key points for your situation:

1. Profitability cases: The cleanest, MECE way is indeed Revenue vs. Costs. That’s the backbone. If profits are declining, they must come from one or both sides. That’s why many McKinsey interviewers expect you to start there.
2. Context buckets: Things like Market, Customers, Competitors are not “wrong,” but they usually fall within Revenue/Cost drivers rather than as a separate top-level bucket. For example:

• Customers → tie to revenue drivers (volumes, pricing, churn)
• Competitors → tie to market share and pricing power (again revenue)
• Regulations → tie to costs

So instead of having a third “understanding the decline” bucket, you can integrate those ideas directly into Revenue and Cost. That keeps you MECE and still allows you to show creativity.

1. Being creative: Creativity is great, but it has to stay relevant. Adding “Societal impacts” in a profitability case would feel forced unless the case prompt explicitly mentions regulatory or ESG angles. Partners prefer sharp, relevant thinking over being abstractly creative.
2. The sample you saw: Sometimes “expert frameworks” online look different (Market, Operations, Customers, Marketing). That’s more like a growth strategy or diagnostic structure. In a McKinsey interview, simpler and more rigorous is better: Profit = Revenue – Costs, then adapt sub-branches with context.

So bottom line:
Start with the Profitability tree. Enrich it with contextual factors (market, competitors, customers) inside the relevant branches. Don’t add extra catch-all buckets unless the case clearly calls for it. Creativity is rewarded when it’s directly linked to solving the client’s problem, not when it’s just decorative.

best,
Alessa :)

I see you've received some content answer already, so I won't repeat that point. 

I wanted though to push back on your assumption that McK Partners care about the nitty-gritty of MECE. Actually, I'd say they care less on average than first round interviewers. 

What they care more about is whether they see you as client ready. As in, would they trust you in front of a client with your current way of thinking, approach, way of engaging? So in that sense, they care more about your emotional intelligence rather than how perfect those buckets are. 

Best,
Cristian

You mentor is right. Sample answer is just wrong. It's just a random laundry list of ideas.

The issue with your 3rd bucket is that it is not at the same level of the other 2.

This is how it should be:

1. Understand why profit is going down - identify numerical driver and underlying cause:

• Analyze Revenues
• Analyze Cost structure

2. Define strategy to get back to profitability:

• Revenue side initiatives
• Cost side initiatives

Now you could break down 1. into two other alternatives:

• 1.1. Identify Numerical Driver - Revenue vs. Cost
• 1.2. Identify Underlying Cause - Customers, Competitors, Supply Chain, Company Decisions

Note: not sure what "market" is if you already have "customers" and "competitors", I believe you have an overlap on that one.