Source: Precision Worldwide, Inc. case report | Course: Managerial/Cost Accounting
Tags: Precision Worldwide, sunk costs, contribution margin, relevant costs, irrelevant costs, product line decision, steel rings, plastic rings, inventory management, cost accounting case study, product transition
Difficulty: Intermediate
Prerequisites: Basic understanding of cost behaviour (fixed vs. variable), contribution margin, and the concept of sunk costs.
This case sits at the intersection of relevant-cost analysis and product-line decision-making, two pillars of any managerial accounting course. Precision Worldwide, Inc. manufactures industrial machines and is weighing whether to discontinue its steel ring product in favour of a new plastic ring. The twist is timing: plastic production cannot begin until September, while existing steel ring inventory lasts only until mid-September. The case forces you to separate costs that matter for the decision (relevant) from costs that have already been spent (sunk), and to think about the reputational consequences of selling an inferior product alongside its replacement.
Precision Worldwide must decide whether to switch from steel rings to plastic rings, and what to do with leftover steel ring inventory during the transition. The core accounting lesson is that past spending on steel rings is a sunk cost and should not influence the forward-looking decision. The decision hinges on the contribution margin of plastic rings and the reputational risk of continuing to sell steel rings once the better product is available.
Sunk cost
A cost that has already been incurred and cannot be recovered, regardless of what decision is made going forward.
Think of it as: money already out the door. Whether Precision sells the remaining steel rings or bins them, the cost of producing that inventory is the same, already spent.
Contribution margin
Selling price per unit minus variable cost per unit. It tells you how much each unit sold contributes toward covering fixed costs and generating profit.
In simple terms, this means: for every plastic ring Precision sells, how much money actually flows toward paying overheads and earning a return?
Relevant cost
A future cost that differs between decision alternatives. Only relevant costs should factor into a business decision.
Think of it as: costs you can still do something about. If a cost stays the same regardless of which option you pick, ignore it for decision purposes.
Irrelevant cost
A cost that does not change between alternatives, or one that has already been incurred (a sunk cost). These should be excluded from the analysis.
In simple terms, this means: noise. It is real money, but it does not help you choose between option A and option B.
Product-line decision
The managerial choice of whether to add, keep, or drop a product from the company's portfolio, based on whether it contributes positively to overall profitability.
Think of it as: deciding which items stay on the menu and which get cut.
Precision Worldwide produces industrial machines and equipment, including steel rings used as components.
Increasing competition has forced the company to consider shifting to plastic rings, which are presumably cheaper or superior for customers.
The production switchover cannot happen until September, creating a gap period.
Precision holds enough steel ring inventory to last until mid-September.
Plastic rings will become available in September, meaning there is an overlap window where both products exist.
The central debate: should Precision continue selling steel rings once plastic rings are available, or stop immediately?
Selling the inferior product alongside the new one risks reputational damage if clients discover they were sold an outdated component.
Step 1: Identify sunk costs. All costs already spent on steel ring production, including existing inventory costs, are sunk. They cannot be recovered and should not influence the go-forward decision.
Step 2: Calculate the contribution margin of plastic rings. This tells Precision whether the new product line is financially viable on its own terms.
Step 3: Assess relevant costs only. The decision to drop steel rings should rest on future cash flows, not on a desire to "recoup" past investment in steel inventory.
Step 4: Factor in qualitative considerations. Reputational risk is not a line item on the income statement, but it is a real cost. Clients who learn they were sold an inferior product may take their business elsewhere.
If Precision believes the steel ring market is dead (customers will prefer plastic), the right move is to stop selling steel rings and absorb the inventory write-off.
If steel rings still have a viable market segment (some customers prefer them, or the plastic alternative is not yet proven), continuing sales may be defensible.
The sunk cost of existing inventory should not be the reason to keep selling. That reasoning is the textbook sunk-cost fallacy.
This is the same logic a technology company faces when deciding whether to keep selling last year's model after launching a new one. Apple, for instance, phases out older iPhones rather than selling them at a discount alongside the new release, partly to protect brand perception. Precision's dilemma mirrors any manufacturer deciding when to cut over from a legacy product to its replacement.
"We should keep selling steel rings to recover the inventory cost." This is the sunk-cost fallacy in action. The inventory cost is already spent. The decision should rest on future revenues and costs, not on recouping the past.
"The contribution margin of the steel rings justifies continued sales." Contribution margin matters, but only if the product can be sold without harming the company's broader position. Reputational damage from selling an inferior product can erode future revenue across all product lines.
"Sunk costs are always irrelevant." Sunk costs are always irrelevant to the decision at hand. They are still real accounting costs that appear on financial statements, and they may affect reported profit. The point is that they should not change your choice between alternatives.
"Dropping the product line means the company loses money." Dropping a product line with a positive contribution margin does reduce total contribution in the short term. But if the replacement product has a higher contribution margin, the loss is temporary.
⚠️ Exams love to test whether you can identify sunk costs in a scenario and exclude them from your analysis. If a question describes money already spent, it is almost certainly testing whether you will fall for the sunk-cost trap.
⚠️ Contribution margin calculations for new products are a staple of product-line decision questions. You will typically need to compute it and then use it to recommend keep, drop, or replace.
⚠️ Qualitative factors (reputation, customer relationships, brand value) frequently appear as the "discuss" or "what other factors" portion of a case question. Do not ignore them just because they are not in the numbers.
⚠️ The distinction between relevant and irrelevant costs is one of the most commonly examined concepts in managerial accounting. Be prepared to classify a list of costs as one or the other and justify each classification.
True or false: The cost of steel ring inventory already on hand is a relevant cost in Precision's decision to switch to plastic rings.
False. It is a sunk cost and therefore irrelevant to the forward-looking decision.
Fill in the blank: The ________ is the difference between selling price per unit and variable cost per unit.
Contribution margin.
True or false: A cost that does not differ between two alternatives should be included in the analysis to give a complete picture.
False. Costs that do not differ between alternatives are irrelevant to the decision and should be excluded from the analysis.
True or false: Reputational risk is not a valid consideration in a product-line decision because it cannot be quantified precisely.
False. Qualitative factors such as reputational risk are valid and often critical considerations, even when they resist precise measurement.
Q: If Precision decides to discontinue steel rings, should the cost of existing steel ring inventory influence that decision? Why or why not?
A: No. The cost of existing inventory is a sunk cost. It has already been incurred and cannot be changed by the decision. Only future costs and revenues that differ between the alternatives (continue vs. discontinue) are relevant.
Q: What is the contribution margin, and why is it important in Precision's decision to adopt plastic rings?
A: The contribution margin is selling price minus variable costs per unit. It matters because it tells Precision how much each plastic ring sold contributes toward covering fixed costs and generating profit. A positive contribution margin for plastic rings supports the case for switching.
Q: Precision's sales team argues that selling the remaining steel rings will generate revenue and should therefore continue. What is wrong with this reasoning?
A: The reasoning ignores two things. First, the inventory cost is sunk and should not motivate continued sales. Second, selling an inferior product alongside its replacement risks reputational harm that could reduce future revenue across all of Precision's product lines. The question is not whether steel rings generate revenue in isolation, but whether selling them is the best use of Precision's market position.
Q: Name two qualitative factors Precision should consider beyond the financial analysis.
A: Customer trust and brand reputation. If clients discover they were sold steel rings when a superior plastic alternative was available, they may question Precision's integrity and take future business to competitors. Additionally, industry reputation matters in industrial equipment, where long-term relationships and reliability are central to purchasing decisions.
Q: Classify the following costs as relevant or irrelevant to the decision to switch from steel to plastic rings: (a) the cost of steel already in inventory, (b) the variable production cost of plastic rings, (c) the selling price of plastic rings, (d) the factory lease payment that does not change regardless of which product is made.
A: (a) Irrelevant, sunk cost. (b) Relevant, it is a future cost that applies only if plastic rings are produced. (c) Relevant, it is a future revenue that differs between alternatives. (d) Irrelevant, it does not change between the two options.
This case connects directly to relevant cost analysis and special-order decisions, where the same skill of filtering out sunk and fixed costs applies. It also links to CVP (cost-volume-profit) analysis, since Precision needs to understand the breakeven point for the new plastic ring line. More broadly, the reputational dimension connects to strategic management accounting, where long-run positioning and customer relationships factor into what would otherwise be a purely numerical exercise.
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