The first few minutes of a case

Find the decision inside the brief

A case opening can contain a business description, a concern and several distracting facts. Before drawing branches, work out what the client needs to decide. "Sales are disappointing" describes a symptom. "Should we change our subscription price to improve operating profit this year?" identifies a decision, a measure and a time horizon. Your structure should make that decision easier.

Listen to the whole prompt before asking questions. Write down the objective in a short sentence, then restate it in enough detail for the interviewer to check your understanding. "We need to find a way to restore this year's operating profit, while keeping the service available in all current cities. Is that right?" If the interviewer corrects you, update the objective before proceeding.

Ask questions that change your approach

Clarification is for resolving ambiguity that matters now. Establish the target measure, time period, business model and any binding constraint if the prompt has left them unclear. You do not need a complete company history before building an initial structure. Asking for every possible dataset can make it difficult to see what you intend to investigate.

Consider a fictional meal subscription company asked to "improve performance." Whether performance means subscribers, cash flow or operating profit changes your analysis. Whether the company delivers meals itself or buys delivery from a partner changes how you describe its costs. Its founder's background is unlikely to change your first investigation. Before asking a question, consider what you would do differently if the answer changed.

Build branches that answer different questions

Ask for a short pause, then organise the problem into questions you can test. For this company, you might first determine why operating profit changed, then compare feasible remedies against the size and timing of the shortfall. For the diagnosis, split revenue into paying subscribers, orders per subscriber and net revenue per order. Separate fulfilment cost per order from fixed operating costs.

"Customers, competition, costs and company" is a set of labels. It becomes an analysis only when you explain what each branch would establish. Overlapping branches are especially troublesome when you calculate an impact. A discount affects net price; counting it again as a marketing expense would exaggerate the profit loss unless the accounting treatment genuinely separates those amounts.

A practical check for a mutually exclusive, collectively exhaustive structure is to try placing the same fact in two branches, then try finding an important fact with no home. Expect to revise the structure as you learn more about the business. State the assumptions that make the structure valid, such as analysing one year and using the same definition of operating profit throughout.

Explain where you would start

Present your structure as a brief argument. "I would first reconcile the profit change into revenue and cost drivers. Because delivery makes up a large share of the cost described in the prompt, I would start with contribution per order and compare it across cities. Then I would test remedies against the annual target and the requirement to keep every city open." The interviewer can follow the diagnosis and see which analysis you propose to do first.

Your first branch is provisional. If the interviewer provides an exhibit that points elsewhere, use it. In an interviewer-led exercise, they may choose the next question. In candidate-led practice, you should propose a focused request and explain why it matters. In both formats, revise the structure when new evidence changes the problem.

Rehearse the opening on its own

Take an unfamiliar prompt and stop before reading any solution. Write the decision, two high-value clarification questions and a structure with a first investigation. Say the opening aloud. Then check whether someone could understand what you want to learn without seeing your page. If the explanation needs a long definition of each bucket, make the labels more concrete.

Repeat with a different business model rather than memorising the same opening. A hospital, software vendor and manufacturer can share a profit identity while having very different operational drivers. The skill is translating the objective into the economics of the business in front of you.