McKinsey Profitability Case 2027: Issue Tree Walkthrough

For the McKinsey profitability case question "A company's profits have declined in the last two years. How would you diagnose the problem?", start with an issue tree: profit equals revenue minus cost, then branch revenue into price times volume and cost into fixed versus variable.

What This Question Assesses in a McKinsey Profitability Case

This is the most commonly reported case type in McKinsey interviews, and it tests structured problem-solving above all. The interviewer is watching whether you break the problem down MECE (mutually exclusive, collectively exhaustive), form hypotheses before drowning in data, and drive the analysis yourself rather than waiting to be led. Candidates commonly report that the difference between a pass and a fail is not business knowledge but discipline: top candidates pick one branch, test it, and move on, while weaker ones list factors without prioritising. The issue-tree approach is commonly reported by candidates as the single most drilled skill before McKinsey interviews.

How to Structure This McKinsey Profitability Case

Walk through the issue tree out loud, then commit to a hypothesis.

• Lay out the tree: Profit = Revenue − Cost. Revenue = Price × Volume (split volume into existing customers versus new customers, and price into list price versus realised price). Cost = Fixed + Variable (split variable into unit economics like materials and labour).
• Form a hypothesis: Before asking for data, state where you would look first and why. "Given the decline spans two years, I would first check whether it is a revenue or cost problem, and within revenue whether volume or price is the driver" shows hypothesis-driven thinking.
• Test with data: Ask for one cut at a time — revenue versus cost trend first, then drill into the weaker branch. Each data point should confirm or kill a hypothesis.
• Synthesise: State the root cause plainly, then recommend actions tied to that cause. A diagnosis without a recommendation is an incomplete case.

Example line: "I would start by separating revenue and cost trends — if revenue is flat while costs rose, I would drill into variable costs per unit versus fixed cost creep to find the driver."

Common Mistakes With the McKinsey Profitability Case

• Listing ideas instead of structuring. Brainstorming twenty possible causes without a tree signals unstructured thinking, which is exactly what the case screens out.
• Never forming a hypothesis. Candidates commonly report that interviewers penalise data-gathering without a point of view — always state what you expect to find and why.
• Ignoring the two-year timeframe. A two-year decline suggests a structural trend, not a one-off shock. Your hypotheses should reflect that.

Cases are won on structured thinking under pressure — drill this framework aloud until the structure flows without notes.

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FAQ

Should I memorise the issue tree? Understand it, do not recite it. Interviewers can tell when a framework is memorised versus internalised — adapt the branches to the specific company.

What if the interviewer gives me a chart? Read it before speaking, state the key insight in one sentence, then link it to your hypothesis. Do not describe every number.

How much time should structuring take? Two to three minutes of clear, calm structuring. Rushing into questions without a tree is a common failure mode.

Preparing for McKinsey's interview? Our 2027 McKinsey Solve Game, RedRock, Sea Wolf, Sustainable Futures Lab, Case Interview Interactive Simulations has practice questions and answers — $79 one-time, instant download.