A good clarifying question prevents you from solving the wrong problem. It settles something that would change your approach: the decision, the measure of success, the business you are analysing or a boundary you must respect.
Before asking a question, imagine two possible answers. If you would proceed in exactly the same way after either answer, I would usually leave it for later.
This is a more useful standard than trying to ask three questions at the start of every case. Sometimes the prompt has already told you everything you need to begin. Sometimes one unfamiliar phrase conceals the most important choice in the case.
Find the gap in the prompt
Listen for what the client needs to decide. Then look for the missing detail that makes that decision ambiguous.
| What is missing? | A useful question | Why it matters |
|---|---|---|
| Success | “What would the client need to achieve for this expansion to be worthwhile?” | Revenue growth, profit and access to a strategic customer can favour different options. |
| Meaning | “Does ‘profit’ here mean operating profit for the city, including fleet costs?” | You need to know which costs and activities belong in the calculation. |
| Scope | “Are we deciding about this city alone or the whole network?” | Closing one location can affect revenue elsewhere. |
| A binding condition | “Can prices change immediately, or only when contracts renew?” | A good annual opportunity may contribute little within the deadline. |
Treat these as things to notice, not a script to recite. If the prompt says the client wants an extra £2 million of operating profit in its UK division next year, asking about the objective, geography and timing again wastes the information you already have.
You can combine closely related gaps naturally: “What improvement does the client need, and by when?” Avoid combining five unrelated requests into one sentence. The interviewer should be able to answer without keeping a list in their head.
Work through an opening: more rides, less profit
Consider this fictional prompt:
An e-scooter operator has increased rides by 18% in its largest city, but profit has fallen. The CEO wants your help.
A tempting first question is “Have maintenance costs increased?” That may become an excellent analytical question. At this point, though, you have not established what the CEO wants you to deliver.
I would begin:
“Are we aiming to restore the city’s previous profit level, or is there a different target?”
The interviewer replies:
“Restore last year’s operating profit within twelve months, while keeping annual rides at least at the current level.”
That answer rules out an easy but incomplete recommendation: shrink the business until profit recovers. You can still change where and when scooters operate, but your proposal must preserve total rides.
One further question is useful:
“Does that operating-profit measure include the fleet and the city’s share of central costs?”
Suppose the answer is yes. You now know that a better contribution per ride is not enough if fleet depreciation or allocated overhead has risen faster.
Carry both answers into the transition:
“I’ll find what has reduced city operating profit and assess how to recover it over twelve months while preserving current ride volume. I’ll compare the change in contribution from rides with fleet and other operating costs, then test the fixes against the volume requirement.”
That is an opening with consequences. The questions have changed both the financial analysis and the criteria for accepting a solution.
Quick Case Opening Drill
A chain of 30 climbing gyms recorded more visits than ever last year, yet operating profit fell. You asked the interviewer what the CEO wants.
- Profit target
- Restore last year's operating profit within twelve months
- Volume condition
- Annual visits must stay at least at current level
Which possible recommendation now conflicts with what the client wants?
Let the answer change the arithmetic
Later in the same case, imagine you learn that annual rides increased from 100,000 to 118,000. Contribution after the costs that vary with each ride stayed at £2. Fixed operating costs increased from £150,000 to £200,000.
| Annual result | Last year | Current year |
|---|---|---|
| Rides | 100,000 | 118,000 |
| Contribution from rides | £200,000 | £236,000 |
| Fixed operating costs | £150,000 | £200,000 |
| Operating profit | £50,000 | £36,000 |
The additional rides contributed £36,000, but the £50,000 increase in fixed costs more than absorbed that benefit. The recovery target is £14,000 of annual profit while keeping at least 118,000 rides.
You might recover £14,000 through lower fixed costs, better contribution per ride or a combination. An extra £14,000 of revenue would only close the gap if it arrived without additional costs. A proposal to return to last year’s smaller fleet also needs a credible explanation of how it would serve today’s ride volume.
This is why clarification belongs in the opening. It gives the later analysis a target and stops attractive-looking calculations from answering a different question.
The answer should change the work you do next.
Save the investigation for your structure
You do not need a full revenue breakdown before you can propose examining revenue. Nor do you need every competitor’s price before deciding whether pricing belongs in the analysis.
Opening questions establish the assignment. Analytical questions investigate it.
For the scooter case, “Which city are we discussing?” may establish scope. “How has contribution per ride changed by neighbourhood?” investigates a possible cause. The second question becomes more effective after you explain why location could account for the profit decline.
The boundary is practical rather than ceremonial. If the interviewer starts giving you the relevant numbers immediately, work with them. You do not need to force the conversation back into an opening sequence just because your practice template puts a framework next.
Handle an answer that gives you very little
An interviewer may say the client has no fixed target, that data are unavailable or that you should make an assumption. Keep moving.
For an expansion without a target, you could say:
“I’ll assess whether it creates an attractive profit opportunity, how much cash it requires and what could prevent execution. If we establish a return threshold later, I’ll compare the economics against it.”
If you must make an assumption, make the assumption useful and visible:
“I’ll start with the UK business because that is the market described. If overseas operations are also in scope, I would include their contribution and any shared costs.”
You are giving the interviewer a clear point to correct. Asking the same question in three different ways rarely creates information that was not available the first time.
When an unfamiliar term blocks understanding, ask directly. “What does a completed connection mean in this business?” is better than building an elaborate analysis around the wrong unit.
Quick Answer Repair Drill
A payroll software firm may expand into small businesses. Told the client has no fixed target, a candidate replies: “Could you give me a rough figure instead?”
What is the best assessment of this reply?
Know when you have enough to begin
You are ready to structure when you can state the decision, identify how you will judge it and understand the main boundary of the work.
You do not need to resolve every uncertainty at the opening; the rest of the case investigates much of it. Ask what you need to begin, listen to the answer and move into the structure.
A natural transition is enough:
“That gives me the scope. I’d like a moment to organise how I would assess it.”
Then build a structure around the specific decision.
Practise the question and the response together
Take a fresh prompt and write your first question. Next to it, write two plausible answers and what you would do differently after each.
If your question concerns a twelve-month versus five-year horizon, show how the shorter horizon changes which benefits count. If it concerns customer access versus profit, change the measures in your structure. This exposes questions that sound professional but do no useful work.
Then practise aloud with a partner who can answer unexpectedly. Review whether you listened, used the answer and moved forward. The wording matters less than the adjustment you make.
Try the case-opening drill on a nonprofit software launch. Your task is to clarify what success means and carry it into the approach. For the complete opening sequence, read how to set up a case.
Case setup drill
How would an MBB interviewer judge your case opening?
Nonprofit Fundraising Platform Enterprise Tier Launch
Clarify a nonprofit software launch. Practise with Casey and get feedback.
Frequently asked questions
Deciding what to ask first
How do I tell whether a clarifying question is worth asking?
Ask it only if the answer could change how you approach the case. Before speaking, imagine two plausible answers. If you would proceed in exactly the same way after either one, leave the question for later. Writing a question beside two answers and your next step for each exposes questions that sound professional but do no useful work.
What should I listen for in the prompt before asking anything?
Listen for the decision the client needs to make, then find the missing detail that makes it ambiguous. Common gaps are the measure of success, the business being analysed and a boundary you must respect. For an expansion, success could mean revenue growth, profit or access to a strategic customer, and each points your structure somewhere different.
Why not open the scooter case by asking whether maintenance costs have increased?
Because it investigates a possible cause before you know what the CEO wants delivered. Rides rose 18% in the largest city while profit fell, and maintenance may later become an excellent analytical question. At the opening, though, you first need to establish the goal of the work so your structure answers the CEO's actual request.
Opening questions versus analysis
What is the difference between a clarifying question and an analytical one?
Opening questions establish the assignment; analytical questions investigate it. In the scooter case, ‘Which city are we discussing?’ may set the scope, while ‘How has contribution per ride changed by neighbourhood?’ tests a possible cause. Asking the second at the opening jumps into analysis before you have agreed what problem you are solving.
Do I need a full revenue breakdown or competitor prices before I can build a structure?
No. You can propose examining revenue without already having the breakdown, and you can decide that pricing belongs in the analysis without knowing every competitor's price. Gather that detail later, when it tests a specific branch of your structure, rather than loading it into the opening.
How can a clarifying answer change the maths later in a case?
It shows which numbers actually explain the result. In the scooter example, rides rose from 100,000 to 118,000 at £2 contribution each, adding £36,000. Fixed operating costs rose from £150,000 to £200,000, an extra £50,000. Profit therefore falls despite more rides, which points the analysis towards the cost increase rather than ride volume alone.
How does asking about the time horizon change my structure?
It changes which benefits count. If the client is judging a decision over twelve months rather than five years, longer-term gains may fall outside what matters. Likewise, learning that the goal is customer access rather than profit should change the measures in your structure. If neither answer would alter anything, the question can wait.
Thin answers and moving on
What if the interviewer says the client has no fixed target?
Keep moving and set a sensible test yourself. For an expansion without a target, say you will assess whether it creates an attractive profit opportunity, how much cash it requires and what could prevent execution. Add that if a return threshold is established later, you will compare the economics against it.
What should I do if data are unavailable or I am told to make an assumption?
Treat it as permission to proceed rather than a dead end. State a reasonable working assumption, make clear how you will judge the decision and continue into your structure. Leave room to revisit the assumption if better information appears, in the same way you would compare against a return threshold introduced later.
Is there a right number of clarifying questions to ask?
No, readiness matters more than a count. You have enough when you can state the decision, identify how you will judge it and understand the main boundary of the work. Ask what you need to begin, listen to the answer, then move into the structure with a brief, natural transition.
Should I resolve every uncertainty before I start structuring?
No. You do not need to settle every uncertainty at the opening, because the rest of the case investigates much of it. Questions about likely causes are better placed inside your structure, where each answer tests a specific hypothesis instead of delaying the start of the analysis.