Author: Taylor Warfield, Former Bain Manager and interviewer

Last Updated: July 14, 2026

 

An outsourcing case interview asks you to recommend whether a company should keep a function in-house or hand it to an external supplier, based on the avoidable cost of doing the work internally versus the all-in cost of outsourcing, plus strategic and risk factors. This guide gives you the exact structure, the hidden cost traps that sink most candidates, and a fully worked make-versus-buy example with the math shown step by step.

 

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Key Takeaways

 

An outsourcing case is won by comparing avoidable in-house cost against the all-in cost of the supplier, then letting strategic and risk factors break the tie.

 

• Outsourcing means handing a function to another company, while offshoring means moving it to another country, so clarify which one the prompt is testing

 

• Structure the case with four buckets: financial impact, strategic fit, execution risk, and qualitative factors

 

• Never compare the supplier price to the full in-house cost, because fixed costs like depreciation often continue after you outsource

 

• Add hidden costs such as shipping, quality inspection, vendor management, and inventory carrying before you calculate net savings

 

• Keep a function in-house when it is a core competency, drives brand quality, or exposes the client to intellectual property theft

 

• Close with a clear yes or no, the dollar impact, the biggest risk, and one next step

 

What Is an Outsourcing Case Interview?

 

An outsourcing case interview is a make-versus-buy problem where you decide whether a client should keep producing something in-house or pay an outside supplier to do it. You weigh the avoidable cost of in-house production against the all-in cost of the supplier, then layer in strategic fit, supplier risk, and brand effects before giving a clear recommendation.

 

The function on the table is usually manufacturing, but it can be anything: IT, customer service, logistics, payroll, or even research. The core question never changes. Is the client better off owning this work or paying someone else to do it?

 

These cases reward clear financial logic paired with business judgment. The math tells you whether outsourcing saves money, and the judgment tells you whether saving that money is worth the strategic cost. A candidate who only runs the numbers will miss half the case.

 

How Common Are Outsourcing Cases in Consulting Interviews?

 

Outsourcing cases are common because make-versus-buy decisions are core consulting work. They appear as standalone cases or as one branch inside a larger profitability or operations case, and they show up most often for manufacturing, retail, industrials, and supply chain clients where sourcing drives a large share of total cost.

 

The topic is not going away. According to Deloitte's 2024 Global Outsourcing Survey of more than 500 executives, outsourcing of legal, tax, and finance functions sits at 64%, 61%, and 51% respectively, while IT outsourcing reaches 76%. Firms advise clients on these decisions constantly, so they test the skill in interviews.

 

There is a fresh twist worth knowing. The same Deloitte survey found that 70% of executives have selectively brought work back in-house over the past five years, and 78% now run Global In-house Centers. Outsourcing is no longer a one-way street, and a sharp candidate who mentions the insourcing trend signals real awareness.

 

In my experience at Bain, outsourcing questions often hid inside cost-cutting or operations work rather than arriving with a neat label. Recognizing the make-versus-buy structure quickly is a real edge, and it is one reason these sit alongside the most common case interview types worth drilling before your first round.

 

How Do You Solve an Outsourcing Case Interview?

 

Solve an outsourcing case in five steps: clarify the objective, build a structure, run the cost comparison using only avoidable costs, weigh strategic and risk factors, then deliver a clear recommendation. The math identifies the savings and the judgment decides whether those savings are worth taking.

 

1. Clarify the objective: confirm what the client cares about, whether that is cost, capacity, quality, or speed, and pin down exactly which function is being outsourced
   
   
2. Build your structure: lay out the financial, strategic, risk, and qualitative buckets out loud so the interviewer can follow your logic
   
   
3. Run the cost comparison: compare the all-in cost of the supplier against the avoidable in-house cost, not the full in-house cost
   
   
4. Weigh strategic and risk factors: decide whether the function is core, how reliable the supplier is, and what happens to brand and employees
   
   
5. Deliver a recommendation: state yes or no, give the dollar impact, name the biggest risk, and suggest one next step

 

The same discipline that wins a profitability case applies here. Lead with structure, do the math cleanly, and connect every number back to the client's objective.

 

What Framework Should You Use for an Outsourcing Case?

 

Use four buckets tailored to the prompt: financial impact, strategic fit, execution risk, and qualitative factors. Financial impact compares avoidable in-house cost to the all-in supplier cost. The other three buckets decide whether the function is core to the business, how risky the supplier is, and what softer effects the move has on brand and people.

 

Do not memorize a rigid template and force it onto every case. The best case interview frameworks are built fresh for the specific problem in front of you, then made MECE so your buckets do not overlap. Here is what each bucket should contain.

 

Bucket	Keep in-house if	Outsource if
Financial impact	Avoidable in-house cost is lower than the all-in supplier cost	Supplier delivers real net savings after hidden costs
Strategic fit	The function is a core competency or competitive advantage	The function is non-core and a distraction from the core business
Execution risk	Supplier quality, reliability, or geopolitics pose a serious threat	Supplier is proven, with backups and strong quality controls
Qualitative factors	Brand depends on in-house quality or intellectual property is at risk	Brand is unaffected and the client can free up capital and focus

 

This structure also works when an outsourcing question appears inside a broader operations case interview. You simply apply the financial bucket to the specific function the client is weighing.

 

Worked Example: Should the Client Outsource Manufacturing?

 

Here is a full worked example with the math shown step by step. The key lesson is that the real savings are far smaller than the headline number once you remove unavoidable costs. Follow the logic and you will avoid the trap that catches most candidates.

 

Prompt: Your client is a consumer electronics maker that produces its own circuit boards in-house. A supplier offers to make the same boards at a lower price. Should the client outsource?

 

Step 1: Understand the current in-house cost. The client produces 5 million boards a year at a total cost of $50M, which works out to $10 per board. That total breaks down into $20M of materials, $18M of labor, $8M of overhead, and $4M of equipment depreciation.

 

Step 2: Calculate the all-in outsourcing cost. The supplier quotes $7 per board, or $35M for 5 million boards. That looks like a clean $15M of savings, but you must add the hidden costs of running an external relationship.

 

• Shipping and freight: $2M for moving boards from the supplier to the client's plants

 

• Quality inspection: $1.5M to test incoming boards and catch defects

 

• Vendor management: $1M for the team that manages the contract and the relationship

 

• Inventory carrying: $1.5M from holding more safety stock to cover longer lead times

 

Hidden costs add $6M, so the all-in outsourcing cost is $35M plus $6M, or $41M. The naive savings look like $50M minus $41M, which is $9M a year.

 

Step 3: Strip out unavoidable costs. The client owns the factory and equipment, so the $4M of depreciation continues whether or not it outsources, and another $3M of overhead is tied to the building. That means $7M of the in-house cost is unavoidable in the short term.

 

Step 4: Calculate the true savings. The avoidable in-house cost is $50M minus the $7M that stays put, which is $43M. Against the $41M all-in outsourcing cost, the real savings are only $2M a year, about 4% of the original budget and more than four times smaller than the headline $9M.

 

This kind of disciplined arithmetic is exactly what strong case interview math looks like. The difference between a $9M answer and a $2M answer is the difference between an offer and a ding.

 

If you want structured drills and feedback on cases like this, my interview coaching pairs you one-on-one with a former interviewer to sharpen exactly these instincts.

 

What Are the Hidden Costs in an Outsourcing Case?

 

The hidden costs in an outsourcing case are the expenses beyond the supplier's quoted price: shipping, quality inspection, vendor management, inventory carrying from longer lead times, and switching costs. Candidates who only compare the supplier price to in-house cost overstate the savings and miss the point of the case.

 

Lead times deserve special attention. A supplier overseas might quote a great unit price, but two-month shipping windows force the client to hold far more inventory, which ties up cash and raises carrying costs. That single factor can erase most of the apparent savings.

 

There are also one-time costs to flag. Transitioning production, qualifying a new supplier, and potentially paying severance or absorbing plant closure costs all hit the income statement before any savings arrive. A good answer separates these one-time costs from the ongoing run-rate.

 

What Non-Financial Factors Matter in Outsourcing Cases?

 

The non-financial factors are core competency, quality and brand, intellectual property risk, supplier and geopolitical risk, employee impact, and strategic flexibility. These often decide the case when the financial gap is small, so you should raise them even when the math points one way.

 

There are five non-financial factors that win or lose these cases.

 

Core competency: if the function is central to how the client competes, outsourcing it hands away a source of advantage. A premium carmaker rarely outsources engine design, because that is the product.

 

Quality and brand: a brand built on craftsmanship or reliability risks real damage if an outside supplier cuts corners. The savings rarely justify a hit to the thing customers are paying for.

 

Intellectual property: handing designs or proprietary processes to a third party, especially in a region with weak enforcement, can leak the client's edge to future competitors.

 

Supplier and geopolitical risk: reliance on a single supplier or a single country exposes the client to disruption. McKinsey research shows supply chain disruptions cost the average company 45% of one year's profits over the course of a decade.

 

Employee and flexibility impact: layoffs from plant closures hurt morale and public image, while a long supplier contract can lock the client into terms that limit future flexibility.

 

Raising these factors is what separates a consultant from a calculator. The same instinct serves you well in a supply chain case interview, where risk and resilience carry as much weight as cost.

 

Outsourcing vs Offshoring: What Is the Difference?

 

Outsourcing means handing a function to a separate company, whether that company is local or overseas. Offshoring means moving a function to another country, whether you keep it in-house or give it to a supplier there. A case can involve one, both, or neither, so clarify the terms before you structure.

 

The distinction matters because the risks differ. Offshoring adds currency swings, tariffs, longer lead times, and geopolitical exposure on top of the usual outsourcing questions. If the prompt mentions a specific country, treat those country-specific risks as their own line of analysis.

 

Candidates often blur the two and lose credibility. Naming the difference cleanly early in the case is a small move that signals precision to the interviewer.

 

How Do You Give a Recommendation in an Outsourcing Case?

 

Give a recommendation in four parts: state a clear yes or no, give the dollar impact, name the single biggest risk, and suggest one concrete next step. Lead with the answer, keep it under 60 seconds, and tie everything back to the client's stated objective.

 

Commit to a side even when the case is close. Interviewers are testing your judgment, and a wishy-washy answer reads as an inability to decide under pressure. You can acknowledge the trade-off while still planting a flag.

 

Sample recommendation: "I recommend the client keep board production in-house. Outsourcing saves only about $2M a year once we strip out unavoidable fixed costs, and that thin margin does not justify the quality and intellectual property risk of handing our core technology to a supplier. As a next step, I would pursue lean improvements in the existing plant to capture savings without the strategic exposure."

 

That closing structure works across nearly every case type, from this make-versus-buy problem to a market entry question. Lead with the decision, support it with one number and one risk, then point forward.

 

Tips to Ace an Outsourcing Case Interview

 

These five tips come straight from coaching candidates through make-versus-buy cases. Each one targets a mistake I see candidates make again and again.

 

Tip #1: Use only avoidable costs in your comparison

 

The single most common error is comparing the supplier price to the full in-house cost. Strip out depreciation, leases, and any overhead that continues after you outsource. The savings shrink fast, and spotting that is what impresses the interviewer.

 

Tip #2: Always quantify the hidden costs

 

Shipping, quality control, vendor management, and inventory carrying are not rounding errors. Name them explicitly and put rough numbers on them. A candidate who only uses the supplier's quote looks naive.

 

Tip #3: Raise strategic factors before the math forces them

 

Do not wait until the end to mention core competency, brand, and intellectual property. Flag them as part of your structure so the interviewer sees you thinking like a consultant, not a spreadsheet.

 

Tip #4: Separate one-time costs from the run-rate

 

Transition costs, supplier qualification, and severance hit once, while savings recur every year. Treat them separately and the client can see the payback period clearly. Blending them together muddies your recommendation.

 

Tip #5: Stress-test the supplier relationship

 

Ask what happens if the supplier raises prices, misses a deadline, or shuts down. A single-source dependency is a real risk, and proposing a backup supplier or a phased rollout shows mature thinking.

 

Drilling these instincts on real cases is the fastest path to fluency. If you want a faster route, my case interview course walks you through proven structures and worked examples so you can crack an outsourcing case interview in as little as 7 days.

 

Frequently Asked Questions

 

What is an outsourcing case interview?

 

An outsourcing case interview asks you to decide whether a company should keep producing a product or service in-house or hand it to an external supplier. You compare the avoidable cost of doing the work internally against the all-in cost of outsourcing, then weigh strategic factors like quality, brand, and supplier risk before recommending a clear answer.

 

What is the difference between outsourcing and offshoring?

 

Outsourcing means handing a function to a separate company, whether that company is down the street or overseas. Offshoring means moving a function to another country, whether you keep it in-house or give it to a supplier there. A case can involve one, both, or neither, so clarify which one the interviewer means before you build your structure.

 

What framework should I use for an outsourcing case?

 

Use four buckets tailored to the prompt: financial impact, strategic fit, execution risk, and qualitative factors. Under financial impact, compare avoidable in-house cost against the all-in cost of the supplier. The other three buckets cover whether the function is core, how risky the supplier is, and softer effects on brand and employees.

 

What is the most common mistake in outsourcing cases?

 

The biggest mistake is comparing the supplier price to the full in-house cost instead of the avoidable in-house cost. Fixed costs like equipment depreciation and facility leases often continue even after you outsource, which means the real savings are much smaller than they first appear. Strong candidates strip out unavoidable costs before calculating savings.

 

Are outsourcing cases common at McKinsey, BCG, and Bain?

 

Yes. Make-versus-buy decisions are core consulting work, so they appear regularly as standalone cases or as one branch of a larger profitability or operations case. They show up most often in interviews tied to manufacturing, retail, industrials, and supply chain clients, where production and sourcing decisions drive a large share of cost.

 

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