Operations Case Study Example: Worked Bottleneck Case

This operations case study example takes a made-up speaker maker, Harlow Audio, from the prompt to a recommendation. An operations case interview example is solved in four moves: map the process into stages, find the bottleneck with weekly capacity math, price each fix against the same gap, and recommend the fix with the best payoff and the lowest risk.

This guide covers the Harlow prompt and clarifying questions, what an operations case is, live operations cases you can practice, the bottleneck and utilization math, three priced fixes, the recommendation, and what separates a strong answer from a weak one.

Practice it live: Titan Motorcycles Operations Optimization is a different client with its own data: a US motorcycle maker whose production costs have risen for three years. It has 8 questions, 4 with math and 3 exhibits, and an AI interviewer runs it out loud.

Operations case study example: the Harlow Audio prompt

Here is the case as an interviewer would give it. Harlow is invented, and so are all of its numbers.

The gap is 300 speakers a week, or 25% more output from a plant that says it is full. Before you structure anything, ask clarifying questions. Here is a good set, with the interviewer's answers.

Q: What is the goal, and what limits us? A: Ship 1,500 speakers a week reliably within one quarter. No new building. Capital spending above $500,000 needs board approval.

Q: How does the plant run? A: Two 8-hour shifts, five days a week, so 80 hours. Every speaker goes through four stages in order: enclosure prep, board assembly, acoustic testing and packing.

Q: What is a speaker worth to Harlow? A: The retailer pays $180 a speaker and variable cost is $120, so each speaker contributes $60. Assume 50 shipping weeks a year.

Q: Is the problem every stage, or one? A: I will give you the stage rates.

Two answers already shape the case. The $60 contribution tells you what the 300-speaker gap is worth, so you can judge any fix against it. And four stages in a fixed order mean one of them is probably setting the pace for the rest.

What is an operations case interview?

An operations case interview gives you a process, not a market. The signals in the prompt: a target for output or speed, a plant, warehouse or call center, and a claim that the system is "at capacity". The operations case interview guide covers the four common types (production, process improvement, cost cutting, capacity planning) and the formulas. This page works one production case end to end. If the prompt is about spend rather than output, the cost reduction case interview guide is the closer fit, and other case types are in the case interview examples collection.

Which operations cases can you practice?

These live library cases are operations problems with their own clients and data, different from Harlow. Each runs as a voice case with an AI interviewer that shows exhibits when you reach them and grades every answer.

Case (style, industry)	Quant difficulty	Qualitative difficulty	The math you run	Median time
Titan Motorcycles Operations Optimization (Bain, motorcycle manufacturing). 8 (4 with math), 3 exhibits.motorcycle manufacturingBainQuant difficulty mediumQualitative difficulty medium21 min· 11 voice runsTry free	medium	medium	Cost per unit growth, outsourcing savings	21 min11 voice runs21 min, 11 voice runs	Try free
MetroFresh Distribution Center Operations Turnaround (McKinsey, grocery distribution). 8 (4 with math), 4 exhibits.grocery distributionQuant difficulty easyQualitative difficulty hard23 min· 17 voice runsTry free	easy	hard	Picking capacity gap, EBITDA initiatives	23 min17 voice runs23 min, 17 voice runs	Try free
Biopharma Outsourcing to Mexico (BCG, biomanufacturing). 7 (1 with math), 1 exhibit.biomanufacturingQuant difficulty easyQualitative difficulty medium22 min· 14 voice runsTry free	easy	medium	Variable cost per unit, annual savings	22 min14 voice runs22 min, 14 voice runs	Try free
Skylight Goods (BCG, manufacturing). 9 (2 with math), 5 exhibits.manufacturingQuant difficulty hardQualitative difficulty mediumFewer than 10 runsTry free	hard	medium	Profit change, setup throughput	Fewer than 10 runsFewer than 10 runs	Try free

Two are adapted from MBA consulting club casebooks (Wharton and Booth); the other two were written for Road to Offer. More are in the case library, 92 cases in all. Every debrief scores seven categories: structure (25% of the score), quantitative analysis (20%), business judgment (15%), and problem understanding, exhibit reading, communication and synthesis (10% each), with feedback on every question. Median times come from completed runs between June 25 and September 22, 2026, and count runs, not people.

How do you structure an operations case?

Structure an operations case around the process, not a generic framework: map the stages, find the one that limits output, explain why it is slow, then compare fixes on cost, size and risk. For Harlow, say it in that order:

1. Map the process. Four stages in sequence: enclosure prep, board assembly, acoustic testing, packing.
2. Find the bottleneck. Convert each stage to speakers per week; the lowest one sets output.
3. Explain the bottleneck. Is it slow because of its rated speed, or because it loses time (changeovers, breakdowns, waiting for material)?
4. Price the fixes. Every option against the same 300-speaker gap and its $900,000 a year of contribution.
5. Check the next constraint. Once the bottleneck moves, which stage binds next?

The interviewer now hands you the first exhibit.

Where is the bottleneck in the Harlow case?

The bottleneck is board assembly: it produces 15 speakers an hour, so 1,200 speakers in an 80-hour week, the lowest capacity of the four stages.

Exhibit 1: stage rates (speakers per hour while running)

Board assembly is rated at 20 an hour, but the changeovers take 4 x 30 minutes = 2 hours of every 8-hour shift. The machine produces for 6 of 8 hours, 75% of the time, so its effective rate is 20 x 75% = 15 speakers an hour. Now put every stage on a weekly basis (rate x 80 hours):

Utilization is output divided by capacity: 1,200 / 1,920 = 62.5% for enclosure prep, and so on. Say the implication out loud: "The plant is not full. One machine is full, and it is losing a quarter of its time to changeovers. Extra shifts on enclosure prep, testing or packing add nothing."

What is the gap worth?

The 300-speaker gap is worth $900,000 of contribution a year: 300 speakers x 50 weeks x $60 per speaker. That number is the yardstick for every fix. A fix that costs more than it recovers is not a fix, however clever.

Which fixes should Harlow consider?

Three fixes close the gap: weekend overtime on board assembly, faster changeovers plus a little overtime, or a second pick-and-place line. The interviewer gives you the costs when you ask.

Exhibit 2: fix options

Option A, overtime only. At 15 an hour, 1,500 speakers need 1,500 / 15 = 100 hours, so 20 extra hours a week. Cost: 20 hours x 2 operators x $45 = $1,800 a week, or $90,000 a year. Net year one: $900,000 - $90,000 = $810,000.

Option B, faster changeovers. Four 12-minute changeovers take 48 minutes, so the line produces for 7.2 of 8 hours, 90% of the time. Effective rate: 20 x 90% = 18 an hour, or 1,440 a week. That leaves 60 speakers a week short, so add overtime: 1,500 / 18 = 83.3 hours, about 3.3 extra hours a week, costing 3.3 x 2 x $45 = $300 a week or $15,000 a year. Total year-one cost: $60,000 + $15,000 = $75,000. Net year one: $900,000 - $75,000 = $825,000. The changeover fix alone adds 240 speakers a week, $14,400 of contribution, so the $60,000 pays back in about 4.2 weeks.

Option C, a second line. Capacity at board assembly doubles to 2,400 a week, but acoustic testing caps the plant at 1,600, so most of it sits idle. Net year one: $900,000 - $400,000 - $120,000 = $380,000. It also ties up $400,000 of capital to fix a problem that is mostly lost time.

What should Harlow do? The recommendation

Harlow should fix the board assembly changeovers now and cover the last 60 speakers a week with about three hours of overtime, which nets $825,000 in year one. Said out loud:

"I recommend Harlow takes the contract and fixes the board assembly changeovers first. Board assembly is the only full stage, and a quarter of its time goes to changeovers. Cutting them from 30 to 12 minutes costs $60,000, pays back in about four weeks and lifts the plant to 1,440 speakers a week. About three hours of weekly overtime closes the rest, so year-one net contribution is $825,000. Overtime alone nets slightly less, $810,000, but needs 20 extra hours every week, which is hard to sustain. A second line nets only $380,000 because acoustic testing would cap output at 1,600 anyway. Two risks: the 12-minute changeover is an estimate, so I would pilot it on one shift first and keep weekend overtime as the fallback; and if the retailer asks for more than 1,600 speakers, acoustic testing becomes the bottleneck."

Practice operations in a real case interview

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What separates a strong answer from a weak one?

A strong operations answer finds the one constrained stage with numbers, asks why it is slow, and prices fixes against the gap; a weak one treats the whole plant as full and buys capacity.

The most common mistake is adding capacity where it is not needed. Extra hours on enclosure prep, testing or packing raise cost and leave output at 1,200, because the board assembly line still sets the pace. The second is skipping the "why": a line rated at 20 an hour that produces 15 is a lost-time problem before it is a capacity problem.

How should you practice operations cases?

Practice operations cases by working the capacity math out loud until it is automatic, then running full cases where you have to find the constraint yourself. Three steps:

• Drill the formulas on paper: capacity = rate x hours x availability, utilization = output / capacity, payback = one-time cost / gain per period. The mental math guide has the shortcuts.
• Rework this case with new numbers: change the changeover time or the contract volume and see when the recommendation flips.
• Run a live operations case with an interviewer who will not tell you where the bottleneck is. The table above lists four.