A strong BCG case conversation needs direction. Explain what you want to find out, why it matters and what the answer would change. When new evidence arrives, use it to choose the next step.
That is the preparation priority I would set before adding more complicated cases. You should be able to move a straightforward business decision forward without waiting for someone to tell you which calculation to perform.
Practise structured thinking, clear communication, explicit assumptions and responding to feedback. Turn those expectations into actions a partner can observe.
Start with the decision that matters
Consider this original practice case. A manufacturer can win a contract for 100,000 components over a year, starting six months from now. It can build a production line or use a subcontractor. The client requires at least £200,000 of incremental contribution after the contract’s additional fixed costs.
Before listing market, competition and capabilities, identify the questions that decide this contract: can either route supply on time, meet the specification and earn the required contribution?
I would check readiness first. An option that cannot serve the contract’s start date needs a credible bridge before its attractive unit cost becomes relevant.
A useful opening sounds like this:
“I would first establish which production routes can supply the full contract on time and to specification. For feasible routes, I would compare the incremental economics with the £200,000 requirement, then test the assumptions most likely to change that result.”
The structure contains an order of work. It tells the interviewer what you will do with the answers.
Choose a question that can change your route
The interviewer confirms that the new line takes nine months and no bridging arrangement is available. The subcontractor can begin in four months and has sufficient capacity.
Set aside the new line for this contract. Do not spend the next five minutes refining its unit margin. The immediate task is to test the subcontractor’s economics and reliability.
If you are told later that the customer can delay the start, you can reopen the build option. A conclusion belongs to its assumptions; changing those assumptions can change the choice.
This is what taking ownership looks like in a case. You explain the next useful test and stay responsive when the interviewer chooses to explore something else.
Read numbers for their implication
The customer will pay £12 per component. The subcontractor charges £9, and managing the contract creates £150,000 of additional fixed costs. Assume all 100,000 components are delivered and paid for, with no other incremental costs.
| Contract economics | Amount |
|---|---|
| Revenue | £1,200,000 |
| Subcontractor cost | £900,000 |
| Additional fixed costs | £150,000 |
| Incremental contribution after fixed costs | £150,000 |
| Client’s requirement | £200,000 |
The subcontracting route is feasible on timing but falls £50,000 short of the financial requirement. That is the insight. Reading every row aloud would make the interviewer do the synthesis.
At the same volume and fixed cost, closing the gap requires another £0.50 per component. You could obtain a price of £12.50, reduce the subcontractor’s charge to £8.50, remove £50,000 of fixed costs, or combine smaller changes.
Each route needs evidence. The customer’s willingness to pay and the supplier’s willingness to reduce its charge are questions to test, not benefits to put into the base case automatically.
Quick Exhibit Drill
A commercial laundry has won a hotel group's linen contract and can wash it in-house or through a partner laundry.
- Profit target
- £120,000 a year from the contract
- Other costs
- Same for both routes
| Route | Loads a year | Margin per load | Extra fixed costs |
|---|---|---|---|
| In-house | 50,000 | £5.00 | £150,000 |
| Partner | 50,000 | £2.80 | £0 |
Which conclusion should the laundry draw from these figures?
Build on a challenge
Suppose the interviewer asks, “Couldn’t we accept £150,000?”
Do not treat the question as an instruction to abandon the objective. Explain the trade-off: “It is a positive contribution, but below the client’s stated requirement. If the contract brings another benefit, such as access to a new customer, I would quantify that separately and ask whether the client is willing to revise the hurdle.”
Now suppose they say the requirement is flexible because the customer offers a credible follow-on contract. You have new information. Explore the follow-on economics and commitments rather than defending your earlier answer as a matter of pride.
Listening well includes distinguishing a new fact, a request to consider an alternative and a challenge to your reasoning. Respond to the actual intervention.
Make creativity solve a specific problem
Creativity is useful when it changes the available choices. In this example, an extended delivery schedule, shared setup cost or customer commitment might improve feasibility or economics.
A long list of ideas such as “use AI, improve marketing and form partnerships” would add little. For each proposal, explain the mechanism and the condition required for it to work.
For example: a customer-funded tooling payment could reduce the manufacturer’s upfront burden, but it would not automatically improve the recurring margin. A longer contract might spread setup costs over more units, but only if the extra volume is sufficiently firm.
You do not need an exotic idea. You need an idea that fits the problem and survives basic scrutiny.
Quick Idea Drill
A family soup maker can win a supermarket's own-label contract, which would be profitable, but the owner cannot fund the new filling line.
- Filling line cost
- £500,000
- Owner's available cash
- £200,000
- Payment due
- In full before the first production run
Sort each idea by whether it solves the owner's actual problem.
Prepare the experience conversation too
Set aside time to discuss your experience, skills and motivation. Cases cover only part of the interview conversation.
Choose examples that show how you worked through disagreement, learned something difficult or changed a decision after receiving evidence. Be precise about your contribution and why you made the choices you did.
For “Why BCG?”, connect something you have learned about the relevant work or office to a concrete interest of your own. A conversation with a consultant is useful when you can explain what it taught you. Repeating that the people were impressive tells the interviewer much less.
Calibrate your practice
Run mocks under the format and timing confirmed for your process. A long teaching case can be valuable for learning, but you also need practice reaching a supported recommendation within the time you will actually have.
Ask partners for observations behind their scores. “Good structure” is less useful than “You identified the delivery deadline and used it to remove an infeasible option.” Retest a correction with a different person or a fresh case.
If an online assessment is part of your invitation, prepare its interaction separately using the instructions supplied by BCG. For the live case, choose an expansion case from the case library and explain which question you would investigate next after every new fact.
Full case practice
Carry it into a fresh case.
Choose a case, work through the decisions with Casey, and review where your reasoning can improve.
Choose a caseFrequently asked questions
Steering the case yourself
How do I give a BCG case direction from the start?
Identify the questions that decide the choice before reaching for generic headings. In the manufacturer example, ask whether either route can supply on time and whether it meets the client's requirement of £200,000 incremental contribution. Market, competition and capabilities matter only where they affect those answers.
What makes a good question to ask the interviewer?
One whose answer could change your route. Asking how long a new production line takes matters because, if it cannot be ready for a contract starting in six months, that option drops out. A question that only refines detail on an option you may discard adds little.
When should I stop analysing an option?
When a fact makes it infeasible for the decision. The new line takes nine months, the contract starts in six and no bridging arrangement exists, so set it aside. Test the subcontractor's economics and reliability instead of refining the line's unit margin, and revisit only if new facts reopen it.
Interpreting numbers and handling pushback
Does the subcontractor route meet the client's requirement?
No, not on these figures. Revenue of £1,200,000 less £900,000 of subcontractor cost and £150,000 of additional fixed costs leaves £150,000 of incremental contribution, short of the £200,000 required. State that implication directly rather than presenting the total and waiting to be asked what it means.
What do I say if the interviewer asks, “Couldn't we accept £150,000?”
Explain the trade-off without abandoning the objective. The contribution is positive but below the client's stated requirement. If the contract brings another benefit, such as access to a new customer, quantify that separately and ask whether the client is willing to revise the hurdle.
Is a challenge from the interviewer a sign that I'm wrong?
Not necessarily. Treat it as something to build on, not an instruction to change course. Restate what the evidence shows, explain what would have to be true for the alternative view to hold and name the fact you would need next. That keeps your reasoning visible and anchored to the objective.
Creativity, experience and realistic practice
How do I show creativity without listing buzzwords?
Offer ideas that change the available choices and explain how each works. In the manufacturer case, an extended delivery schedule, shared setup cost or customer commitment could improve feasibility or economics. Ideas like “use AI, improve marketing and form partnerships” add little because they lack a mechanism and a condition.
How do I judge whether a creative idea is worth raising?
Link it to the gap it must close. The subcontractor route falls £50,000 short of the requirement, so a proposal such as sharing setup cost or securing a customer commitment should show how it improves the economics and what the client or customer must agree to for it to work.
What experience examples suit a BCG interview?
Ones showing how you worked through disagreement, learned something difficult or changed a decision after receiving evidence. Be precise about your own contribution and why you made each choice. The last type pairs naturally with the case skill of changing route when new facts arrive.
How should I answer “Why BCG?”
Connect something specific you have learned about the relevant work or office to your own experience and interests. A general remark about the firm's reputation tells the interviewer little. A concrete link shows you have researched the role and thought about why it suits you.
Are long teaching cases good practice?
Yes for learning, but not enough on their own. Run mocks under the format and timing confirmed for your process, because you also need practice reaching a supported recommendation within the time you will actually have. Use longer cases to build skills, then rehearse under realistic constraints.
What feedback should I ask mock partners for?
The observations behind their scores, not just labels. “Good structure” is less useful than “You identified the delivery deadline and used it to remove an infeasible option.” Specific notes show what to repeat or fix, and you can then retest the correction in a later mock.