Operations questions test a different kind of thinking than finance ones: how a business actually moves inventory, manages production, and keeps a supply chain from breaking under pressure. This deck introduces the core concepts, like the bullwhip effect, through simple explanations first, building toward the vocabulary interviewers expect you to use fluently. No operations background needed, just a willingness to think about a business as a physical system, not just a spreadsheet.
16 cardsConsultingFree, no signup
Card 1 of 16
A partner tells you your next case is “an operations case.” In plain terms, what part of a business does operations actually cover?
Operations is everything a company does to turn inputs into a product a customer actually receives.
Operations is the machinery of the business: buying materials, making the product, moving it around, and getting it into a customer's hands. Where a marketing question asks who will buy and a pricing question asks what to charge, an operations question asks how the thing gets made and delivered, at what cost, at what speed, and how reliably. Almost every operations case comes down to one of those three levers. Interviewers like the topic because the answers are concrete and countable, so vague structure gets exposed fast.
Card 2 of 16
Calder Foods buys wheat and sells boxed cereal. Walk me through its supply chain, stage by stage, and tell me why the stages are worth naming out loud.
A supply chain is the full run of hands a product passes through from raw material to end buyer.
A supply chain is every organization and step involved in getting a product from raw material to final buyer. For Calder that runs roughly: farms grow the wheat, a mill processes and sells it, Calder's plant turns it into cereal and packs the boxes, a distributor stores and moves the cases, a retailer stocks the shelf, and a shopper buys one. Goods move one way while orders and cash move back the other. Naming the stages first matters because each handoff adds cost and time and is a candidate location for the problem you've been asked to solve.
Card 3 of 16
What do “cycle time” and “throughput” mean on a production line, and how do the two connect?
Cycle time is the gap between finished units and throughput is how many finish per hour.
A process is just a sequence of steps a unit passes through. Cycle time is the gap between one finished unit coming off the end and the next one, and throughput is how many units the line actually completes per hour or per day. They're two readings of the same fact: if a finished unit appears every 3 minutes, throughput is 20 an hour. Capacity is the highest throughput the line could hold if nothing went wrong. Get these three words straight early, because most operations cases are an argument about which one the client should be moving.
Card 4 of 16
At Dunmore Assembly Co.'s plant, three of four stations sit idle for stretches during the shift, yet the plant still can't hit its daily output target. Where should you start looking, and why?
A bottleneck is the slowest station in a process, and it caps what the whole system can produce.
Start by finding Dunmore's bottleneck: the single stage in the process with the least capacity, which sets the ceiling on how much the entire line can produce no matter how efficient every other stage is. That's consistent with what the plant manager is describing, the idle stations are simply waiting on the slow one. Speeding up any other stage won't help, since output still can't exceed what the bottleneck allows, so improving the process starts with finding that constraint and fixing it first.
Card 5 of 16
Your client, NorthPeak Manufacturing, is missing its quarterly output targets even though the plant manager insists the machines are running nearly non-stop. Before diving into the process itself, what metric would you check first, and what would it tell you?
Capacity utilization shows what share of a company's maximum output it's actually using.
Start with capacity utilization: it measures how much of NorthPeak's total production capacity is actually being used, shown as a percentage of the maximum possible output. Low utilization can point to inefficiency or weak demand pulling orders away from the plant, while very high utilization is a warning sign too: the plant is close to its ceiling and at risk of bottlenecks if demand climbs any further. Either reading points you toward a different next question, which is exactly why it's worth checking before you go any deeper.
Card 6 of 16
Northbay Logistics' CFO points at a full warehouse and asks why the company is sitting on stock that earns nothing today. Why hold inventory at all, and what does holding it cost?
Inventory buys smooth operations, paid for in tied-up cash, storage and goods going stale.
Inventory exists because supply and demand don't run on the same clock: goods arrive in big batches, customers buy in ones and twos, and nobody knows exactly what next week looks like. Stock on the shelf lets Northbay serve a customer today instead of after the next delivery. The cost is real, though. Cash is parked in the warehouse rather than earning a return, you pay for space, handling and insurance, and goods can spoil, get damaged or go out of date. A common rule of thumb puts the total holding cost near 20 to 30 percent of the inventory's value a year, though it varies widely by industry.
Card 7 of 16
What is safety stock, and why do companies hold it? What's the cost of holding too much?
Safety stock is the buffer inventory that absorbs surprise demand spikes or supply delays.
Safety stock is extra inventory held beyond what's expected to be needed, acting as a cushion against uncertainty, like a sudden spike in orders or a delayed shipment. It lowers the risk of running out of stock, but it isn't free: it ties up capital and storage space, so companies weigh that cost against the protection it buys them. In a case, a client with chronic stockouts and a client with bloated warehouse costs can both trace back to the same lever, just tuned in opposite directions.
Card 8 of 16
What is lead time, and why do interviewers ask about it in operations cases?
Lead time is the full clock from placing an order to actually having it in hand.
Lead time is the total stretch between placing an order and actually receiving it, covering everything from processing and production to shipping. The shorter it is, the less safety stock a client needs to keep on hand to reliably meet customer demand, since there's less time for something to go wrong or for demand to shift in between. When a case involves a supplier switch or a new distribution route, lead time is usually the first number worth asking for.
Card 9 of 16
What is Economic Order Quantity (EOQ), and why is it a useful reflex in an operations case?
EOQ finds the order size where ordering costs and holding costs balance out to the lowest total cost.
Economic order quantity is the order size that minimizes total inventory cost, balancing two costs that pull in opposite directions: the fixed cost of placing an order, and the cost of storing the units once they've arrived. Order too little and you pay that fixed ordering cost too often; order too much and you pay more to store the excess. EOQ is simply the quantity where those two costs are lowest combined, which is why it's a handy structure to reach for whenever a case turns on 'how much should the client order at a time.'
Card 10 of 16
What is Just-In-Time (JIT) inventory management, and what's the tradeoff a case interviewer wants you to name?
JIT brings materials in only as production needs them, trading safety stock for leaner inventory.
Just-in-time inventory management brings materials and components in right as production needs them, instead of stockpiling them in advance. That keeps holding costs and waste low, since there's little excess inventory sitting around. The tradeoff is fragility: with barely any buffer stock, a single disruption anywhere in the supply chain can quickly bring production to a halt. It's a favorite lever in operations cases: a client chasing the cost savings is also signing up for that exposure, and naming the tradeoff explicitly is what separates a strong answer from a list of definitions.
Card 11 of 16
Bramwell & Co., a mid-sized furniture maker, is debating whether to keep building sofas against a demand forecast or switch to starting production only once a customer order comes in. What are the two production models on the table, and what's the tradeoff?
Push production guesses ahead of demand; pull production only makes what's already been ordered.
Bramwell is weighing a push system, which produces to a forecast, building up inventory ahead of actual orders in the hope demand shows up to match it, against a pull system, which flips that logic: production only kicks off once a real customer order actually appears. Pull is the thinking behind JIT and cuts the risk of building sofas nobody ends up wanting, but it generally means longer wait times for the customer and less room to smooth production volume.
Card 12 of 16
Vantor Appliances wants to cut a two-dollar-per-unit inspection at the end of its line to save money. How would you frame the cost of quality for them?
A defect gets roughly ten times more expensive to fix at every stage it slips past.
Quality spending falls into two buckets: what you spend to stop defects, designing the process well and inspecting output, and what you spend once one gets through, scrapping or reworking it inside the plant, or handling a return, warranty claim or recall after a customer has it. The widely used rule of thumb is that a defect costs about ten times more at each stage it escapes, so a dollar of prevention saves ten in rework and a hundred in warranty. It's a rule of thumb rather than a law, but the shape holds: Vantor is trading a small known saving for a large unknown cost.
Card 13 of 16
What is Six Sigma, and how can its framework help structure a case answer?
Six Sigma hunts down process defects using data, aiming for near-flawless, 3.4-in-a-million quality.
Six Sigma is a data-driven methodology for shrinking defects and variability in a process, aiming for a quality level where only about 3.4 defects occur per million opportunities. Teams typically work through it using DMAIC, a five-step cycle: Define the problem, Measure current performance, Analyze the root cause, Improve the process, and Control it so the gains stick. That same define-measure-analyze arc is a useful skeleton for walking an interviewer through any client process problem, not just a formal Six Sigma engagement.
Card 14 of 16
A client wants to move final assembly to a lower-cost country and shows you the wage saving. Beyond that number, what would you check before calling it a good idea?
Offshoring trades a visible wage saving against longer lead times, thinner control and more risk.
First get the words straight: outsourcing means paying an outside firm to do a step you used to do yourself, offshoring means moving the work to another country, and a client can do either, both or neither. The wage saving is the easy number, so your value is the rest of the landed cost, freight and duties, tighter quality oversight, currency swings, and the extra inventory needed to cover a lead time that just went from days to weeks. There's a strategic filter too: don't hand out the step you actually compete on, since a cheaper version of the thing customers choose you for is rarely a saving.
Card 15 of 16
Ferrow Retail Group's category buyers see it every quarter: a small uptick in weekend foot traffic at stores turns into wildly swinging order quantities from their manufacturers a few weeks later. What's happening, and what's it called?
Small demand blips get amplified into big order swings the further upstream you look.
This is the bullwhip effect: a small shift in real customer demand gets amplified as it passes upstream, from retailer to distributor to manufacturer, because each link tends to over-adjust its own orders instead of passing the true signal along unchanged. Those small overreactions stack at every step, so by the time the signal reaches Ferrow's manufacturers, a minor blip in weekend traffic looks like a huge swing in orders, distorting what's actually happening at the register.
Card 16 of 16
Grenwood Instruments' on-time delivery has slipped from 96 percent to 74 percent over two quarters with no change in total demand. Walk me through how you'd diagnose it end to end.
Walk one order from entry to shipment and find the first stage where planned and actual come apart.
Take one order and walk it from the moment it's placed to the moment it ships, comparing what each stage is supposed to take against what it now takes. With demand flat, the lost time sits in one of three places: capacity, where a stage is running above the utilization it can sustain, process, where a stage's cycle time got longer through a new part, new staff or more rework, or supply, where a supplier's lead time has quietly stretched and starves a stage. Confirm the bottleneck with data before recommending anything, since fixing a stage that isn't the constraint moves nothing at all.
Reading is not the same as remembering. Study this deck with scheduled review so the cards come back before you forget them.