When a case interview gives you incomplete information, clarify the decision, organise the problem and make assumptions visible. You do not need to pretend the missing facts are known. Explain what you would check and how a different answer could change your recommendation.

This approach suits practice discussions about business problems. It is not a promise that every employer uses the same case format. Follow the brief and distinguish a live discussion from a written assessment with restrictions on questions or outside assistance.

1. Restate the decision in plain language

Begin with the question the decision-maker needs answered. “Should the team extend opening hours?” is more precise than “Analyse the business.” Confirm the objective and relevant constraints before proposing solutions.

If clarification is allowed, ask one focused question that affects your approach. Avoid a long sequence of questions that delays all reasoning. When no clarification is possible, state a reasonable working interpretation and keep it separate from the facts supplied in the case.

2. Separate known facts from assumptions

Make a short list of what the brief establishes and what it leaves open. For an opening-hours example, current hours might be known while additional staffing cost is unknown. Label any placeholder used for practice.

Do not turn a plausible guess into an apparent market statistic. If you estimate, explain the basis and uncertainty. An interviewer should be able to identify which parts of your conclusion are supported by the brief and which depend on a condition still to be checked.

3. Break the problem into useful parts

Choose a structure that helps answer this particular decision. For opening hours, you might examine demand during the proposed period, operating requirements and the effect on existing service. Explain why these parts matter.

Avoid forcing every case into a memorised framework. A structure is useful when it prevents important questions being missed, not when it adds impressive terminology. Keep the parts distinct enough that you do not count the same cost or benefit twice.

4. Prioritise the uncertainty that could change the answer

Identify which missing fact has the greatest potential to reverse the recommendation. If there is no evidence of demand during the additional hours, that may deserve attention before designing promotional materials.

State what information would reduce the uncertainty and how you would obtain it in a real project. In the interview, use only the data and methods permitted. Do not claim you have verified external demand merely because you can imagine a customer who might be interested.

5. Show calculations with units and checks

When numbers are supplied, name the units and period before calculating. A daily cost and monthly revenue cannot be compared directly. Write intermediate steps clearly enough that an error can be located.

Check whether the answer is plausible against the inputs. If you notice a mistake, correct it and explain the effect. Avoid defending an incorrect result to appear confident. A transparent correction is more useful than quietly changing the conclusion without acknowledging why.

6. Compare options and their trade-offs

Present more than a slogan. Options could include keeping current hours, testing a limited extension or making a broader change. Explain the conditions under which each option is reasonable and what it would require.

Do not describe a pilot as automatically cheap or risk-free. Specify its scope, practical constraints and the evidence it would provide. Where the case lacks enough information to choose confidently, make a conditional recommendation rather than inventing certainty.

7. Finish with a decision and next check

Give a concise recommendation, the main supporting reason and the most important limitation. Then identify the next piece of evidence or action needed. Keep the ending tied to the original question.

For example: “I would test a limited extension only if staffing is feasible, because demand in those hours is still unverified. I would review the agreed demand and cost measures before expanding.” This is hypothetical wording, not a recommendation for an actual business.

Worked fictional case

A fictional service desk is considering an extra evening session. The brief gives current staffing but no evidence about evening demand. Define the decision, separate the missing demand information from the known staffing constraint and compare a limited test with no change. Your answer should explain what the test would measure and what would cause you to stop or revise it. Do not invent customer numbers to make the case look complete.

Practice checklist

  • Can another person identify your recommendation within a few sentences?
  • Are assumptions labelled and units consistent?
  • Have you addressed the constraint in the brief?
  • Can you explain what evidence would change your mind?

Is an incomplete answer always a failure?

You cannot infer the employer’s scoring. Focus on clear reasoning, the available evidence and the instructions.

Should I use a memorised framework?

Only if it helps answer the actual question. Explain the logic in ordinary language.

For presenting your conclusion, use the interview presentation questions guide.