For a Deloitte case interview, practise explaining how a proposed change improves the client’s actual outcome. A new system, process or operating model needs a mechanism: what changes, who uses it and why the result gets better.
I would start there before learning another list of transformation terms. If you cannot explain the mechanism in ordinary language, the recommendation is not ready.
Use the case to demonstrate clear thinking and practical judgment. Explain the assumptions behind your answer and the next step needed to act on it.
Choose preparation that matches the job
Read the role description for the work you would actually do. Strategy, technology, operations, people change and specialist roles can ask you to bring different kinds of knowledge to a problem.
The US recruiting page links separately to a case tool for entry-level Consultative Offerings and a scenario tool for Audit & Assurance. Use the route relevant to your application. A practice category on a website does not replace the instructions for your interview.
For experienced roles, identify the decisions your past work equips you to make. Prepare to explain both your recommendation and the evidence you would need before acting on it.
Trace the whole process
Try this original exercise. A factory wants to increase shipments. Its current daily capacities are:
| Stage | Units per day |
|---|---|
| Filling | 1,200 |
| Packing | 900 |
| Customer demand | 1,100 |
A vendor proposes a filling machine capable of 1,500 units a day. Will it increase shipments?
Under the stated conditions, no. Packing still limits finished output to 900. The client would have a faster upstream step without more saleable units leaving the factory.
Explain that before discussing the machine’s features. Then investigate packing: is the limit caused by equipment, staffing, changeovers, quality rework or scheduling? The cause determines the useful intervention.
Quantify the benefit of the relevant change
Suppose a packing upgrade can raise that stage to 1,100 units a day. It costs £80,000 upfront and adds £30,000 in annual operating costs. The factory operates 250 days a year and earns £4 contribution on each additional unit sold. Assume all other stages can support the extra output.
The upgrade allows 200 more units a day. Annual additional contribution before the new operating cost is:
200 × 250 × £4 = £200,000.
Net annual cash benefit after the £30,000 operating cost is £170,000. At steady operation, simple payback is £80,000 ÷ £170,000, or about 0.47 years.
The useful conclusion is that the packing upgrade addresses the constraint and has attractive economics under the supplied assumptions. That is stronger than saying “automation improves efficiency.”
Quick Case Math Drill
A hand car wash turns drivers away most days. Drying is its slowest stage, while washing and queue space could handle more cars. It is considering new dryers.
- Drying capacity
- 120 to 150 cars a day
- Contribution per car
- £5
- Extra running cost
- £15,000 a year
Across 300 trading days, what annual net benefit would the new dryers support?
Put implementation timing into the answer
The interviewer now says the upgrade takes six months to install. Benefits begin only after it is operational. Assume the operating year is split evenly and the extra operating cost also begins at go-live.
The first year contains half the annual benefit: £85,000. After the £80,000 investment, first-year net cash is only £5,000.
The steady-state payback calculation was not wrong. It answered a different timing question. If the client needs a large cash improvement this year, installation timing becomes central to the recommendation.
This is an easy place to show practical judgment. State when benefits begin instead of presenting a full year of savings as though the equipment were already working.
Test the dependency behind the forecast
A further fact arrives: the materials supplier can support only 1,000 units a day. The packing upgrade would now increase shipments by 100 rather than 200 units.
Annual net benefit becomes 100 × 250 × £4 − £30,000 = £70,000. With the same six-month installation period, first-year net cash becomes £35,000 − £80,000 = −£45,000.
Your next question is whether the supplier limit can be removed, at what cost and by when. The recommendation should reflect the lower supported benefit until that dependency is resolved.
A good answer can change. What matters is whether you can explain which fact changed it.
Quick Prioritisation Drill
A craft brewery plans a £40,000 canning upgrade to lift output from 800 to 1,000 cases a day. Then the can supplier confirms a daily limit.
- Can supply supported
- 900 cases a day
- Margin per case
- £5
- Trading days
- 250 a year
In what order should you test whether the forecast still holds?
- Recalculate the annual benefit on 100 cases: 100 × 250 × £5 = £125,000, half the forecast
- Ask whether the can limit can be lifted, at what cost and by when, against the £125,000 a year at stake
- Compare the planned 200-case uplift with can supply to find the supported uplift of 100 cases
Turn “manage the rollout” into concrete work
A delivery plan should identify the work that makes the benefits possible. In this example, operations owns the packing change, procurement confirms material supply, finance validates incremental costs and the plant team tests output before relying on the new capacity.
Choose measures that reflect the objective: completed units shipped, quality acceptance, downtime and net cash benefit. Machine speed alone is insufficient.
A pilot or commissioning test should have an explicit decision attached to it. For example, confirm that the upgraded packing process can sustain the required output without increasing rejected units before committing to a larger customer order.
Avoid inventing a lengthy implementation programme when the case asks for a short recommendation. Name the dependency and the next action that will resolve it.
Use your experience to sharpen the discussion
Deloitte Australia’s recruiting advice encourages more experienced candidates to identify data that could prove or disprove their hypotheses. That is a useful preparation standard.
If you have worked in operations, explain which observation would distinguish an equipment problem from a scheduling problem. If your background is technology, explain how you would determine whether a system is the constraint or merely where the problem becomes visible.
Keep the case’s facts in charge. Your previous employer’s situation can suggest a question, but it does not establish the answer for this client.
Rehearse the recommendation and the follow-up
Ask a partner to give you the factory example in stages. After each new fact, state what you now recommend and what you would investigate next. The test is whether the output, economics and implementation assumptions remain consistent.
Use the capacity-utilisation framework to practise identifying the constraint in a different process. Then try an unfamiliar full case from the case library.
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 caseFor the real assessment, follow the tools and research instructions attached to your task. Permission to use AI in a preparation exercise does not establish permission during a live assessment. Practise in the conditions your invitation confirms.
Frequently asked questions
Matching preparation to your Deloitte role
Is the Deloitte case interview the same for every role?
Not necessarily, so read the role description first. Strategy, technology, operations, people change and specialist roles can draw on different knowledge. Deloitte's US recruiting page links separately to a case tool for entry-level Consultative Offerings and a scenario tool for Audit & Assurance. Use the route that matches your application rather than a generic practice category.
How can experienced candidates make their background count?
Use your background to name the data that would prove or disprove your hypothesis, as Deloitte Australia's recruiting advice encourages. An operations specialist might explain which observation separates an equipment problem from a scheduling problem. A technology specialist might show how to tell whether a system is the real constraint or merely where the problem becomes visible.
Working through the factory example
Why would a faster filling machine not increase shipments?
Because filling is not the constraint. Packing handles only 900 units a day, so finished output stays at 900 whether filling runs at 1,200 or 1,500. The vendor's machine adds capacity at a stage that already exceeds the bottleneck. Explaining this mechanism in plain language matters more than knowing transformation terminology.
What limits output once packing is upgraded to 1,100 units a day?
Customer demand becomes the ceiling, also at 1,100 units a day, and filling at 1,200 has spare capacity. The upgrade therefore adds 200 units a day, assuming the other stages can support it. Check for the next constraint whenever you relieve one, because the gain is capped by the lowest stage or demand level.
How do I calculate the annual benefit of the packing upgrade?
Multiply the extra units by operating days and contribution, then subtract the new running costs. That is 200 units × 250 days × £4, which gives £200,000. Less £30,000 of annual operating cost, the net benefit is £170,000 a year. Against the £80,000 upfront cost, steady-state payback is roughly half a year.
Why does a six-month installation change the answer?
Benefits start only at go-live, so the first year captures half the annual net benefit: £85,000. After the £80,000 investment, first-year net cash is just £5,000. The steady-state payback was not wrong. It answered a different timing question, so state which view you are using when you present the economics.
What happens if the materials supplier can support only 1,000 units a day?
The upgrade now adds 100 units a day instead of 200. Annual net benefit becomes 100 × 250 × £4 less £30,000, which is £70,000. With the six-month installation, first-year net cash is £35,000 minus £80,000, a loss of £45,000. A dependency outside the factory has halved the extra output.
Should I reject the upgrade once first-year cash turns negative?
Not automatically. The upgrade still produces £70,000 of net benefit in each full year, so the weak first year reflects the installation timing combined with the supply limit. Next, ask whether the supplier limit can be lifted, at what cost and how quickly. The answer determines whether the original case can be restored.
Delivery plans and rehearsal
What does a concrete rollout plan look like in a case answer?
Name the work and the owner behind each benefit. In the factory example, operations owns the packing change and procurement confirms material supply. Finance validates incremental costs, and the plant team tests output before anyone relies on the new capacity. This is more convincing than saying you would manage the rollout.
Which measures should I propose for tracking the change?
Choose measures tied to the objective: completed units shipped, quality acceptance, downtime and net cash benefit. Machine speed alone is insufficient, because a faster machine can sit behind another constraint and leave shipments unchanged. A pilot or commissioning phase lets you confirm these results before the business depends on the new capacity.
How should I practise this kind of case with a partner?
Ask your partner to reveal facts in stages, such as the installation time and then the supplier limit. After each one, state your current recommendation and what you would investigate next. The test is whether your output, economics and implementation assumptions stay consistent as the case changes, not whether your first answer survives.