Case frameworks
The profitability framework for case interviews
Updated 4 min readBy the MECE Editorial Team
Short answer
The profitability framework breaks profit into revenue and costs, then revenue into price and volume, and costs into variable and fixed. Use it to find why profit changed and what to do about it: let the numbers show which branch moved, then look for the business reason behind the number.
Key takeaways
- Profit = revenue − costs; revenue = price × volume; costs = variable + fixed.
- Locate before you explain. Find which branch moved, by how much, before brainstorming causes.
- Segment the branch that moved by product, channel, region or customer.
- Ask whether it is company-specific or industry-wide. The fix differs.
- Recommend fixes that match the cause, with a size for each.
What is the profitability framework?
It is an equation turned into a tree, which is why it is MECE by construction. Every dollar of profit change has to show up as a change in price, volume, variable cost or fixed cost.
Profit = revenue − costs
Revenue
- Price per unit
- Units sold (split by product, channel, region or customer)
Costs
- Variable costs (cost per unit × units)
- Fixed costs (rent, salaries, overhead, depreciation)
How do you solve a profitability case?
Clarify the goal
Profit or margin? How much did it fall, over what period? Are competitors seeing the same thing?
Split and compare
Ask for revenue and costs this year and last. Which moved, and by how much?
Drill into the branch that moved
Split it again: price vs. volume, or cost line by cost line. Then segment it by product, channel, region or customer.
Find the root cause
Internal (a decision, a process) or external (competitors, customers, suppliers, regulation)? Industry-wide or company-specific?
Recommend
Match fixes to the cause and size each one. Separate quick wins from structural changes.
Worked example: why is a sporting-goods chain's profit down by half?
The client is a fictional Ohio chain of 25 sporting-goods stores. Profit fell from $8M to $4M in a year even though sales grew. All figures are illustrative.
| $ millions | Last year | This year | Change |
|---|---|---|---|
| Revenue | 100.0 | 104.0 | +4.0 |
| Cost of goods sold | 60.0 (60% of sales) | 66.6 (64% of sales) | +6.6 |
| Store labor | 20.0 | 21.0 | +1.0 |
| Occupancy and overhead | 12.0 | 12.4 | +0.4 |
| Profit | 8.0 | 4.0 | −4.0 |
- Revenue rose $4.0M, but costs rose $6.6M + $1.0M + $0.4M = $8.0M, so profit fell $4.0M
- Gross margin fell from 40% to 36% (cost of goods went from 60% to 64% of sales)
- If cost of goods had stayed at 60%: $104M × 0.60 = $62.4M, which is $4.2M less than actual
- So the margin squeeze ($4.2M) explains more than the whole $4.0M drop
Now drill into cost of goods. A higher cost ratio can come from suppliers raising prices, a mix shift toward low-margin products, more markdowns, or more theft and damage ("shrink"). Suppose the interviewer reveals that clearance sales rose from 8% to 15% of revenue after the chain over-ordered winter gear before a warm winter. The root cause is a buying problem, not a pricing or cost problem.
What questions should you ask in a profitability case?
- How is the business model set up: what do we sell, to whom, through which channels?
- Over what period did profit change, and is it a sudden drop or a gradual slide?
- Did revenue, costs or both move? Which lines moved most?
- Is this happening to competitors too?
- Has anything changed recently: prices, product mix, suppliers, new stores, new rivals?
How does the profitability framework change by industry?
The tree stays the same, but each industry has its own natural drivers. Using them shows business judgment.
| Industry | Revenue drivers | Cost drivers |
|---|---|---|
| Retail | Store traffic × conversion × average basket | Cost of goods, store labor, occupancy, shrink |
| Airlines | Seats flown × load factor × average fare, plus extras | Fuel, crew, aircraft ownership, airport fees; tracked as cost per available seat mile |
| Restaurants | Covers (guests) × average check | Food and labor as a share of sales ("prime cost"), rent |
| Subscription software | Customers × revenue per customer; new, expansion and churned revenue | Hosting, support, sales and marketing, R&D |
| Manufacturing | Capacity × utilization × price | Materials, energy, labor, fixed plant costs |
What are the most common profitability case mistakes?
- Brainstorming causes before locating the problem. Ten guesses are not a structure.
- Treating margin and profit as the same thing. Profit can fall while margin holds, if volume falls.
- Stopping at "costs went up". Which cost, why, and is it permanent?
- Recommending price increases by reflex, without checking customers and competitors.
- Ignoring mix. Selling more of a low-margin product lowers average margin even if nothing else changes.
Practice this with a live case
Reading builds recognition; solving builds skill. Each case below runs with MECE's AI interviewer, which answers your clarifying questions, pushes back and scores you out of 100.
Profitability · Grocery retail · medium
A Midwest grocery chain's margins have nearly halved Practice liveProfitability · Restaurants · easy
Why is a Southeast restaurant chain suddenly losing money? Practice liveProfitability · Airlines · medium
A low-cost airline's unit costs are rising faster than fares Practice liveProfitability · Pharmaceuticals · hard
A pharma company's top drug loses patent protection next year Practice live
Browse all 50 case interview examples and 50 market sizing questions.
Frequently asked questions
What is the profitability framework in a case interview?
A tree that splits profit into revenue (price × volume) and costs (variable + fixed). It is the most common case structure because every profit change has to appear in one of those branches.
What if both revenue and costs changed?
Quantify both and start with the bigger effect on profit. Often a cost ratio (costs as a share of sales) is more telling than absolute costs when revenue also moved.
What is the difference between profit and margin?
Profit is dollars (revenue minus costs). Margin is profit as a percentage of revenue. A company can grow profit while its margin shrinks, or the reverse.
Keep learning
- FoundationsIssue trees: how to break down any business problemRead the guide
- FoundationsCase interview math: the formulas and shortcuts you needRead the guide
- Case frameworksCost reduction framework: where to cut, and what to protectRead the guide
- Case frameworksPricing strategy framework: how to set a price in a caseRead the guide
MECE (mece.in) is an AI practice platform for case interviews and business problem solving, named after the consulting principle Mutually Exclusive, Collectively Exhaustive. It is not affiliated with McKinsey or any other consulting firm. Companies in worked examples are fictional and their figures are illustrative.
