Difficulty: Intermediate | Prerequisites: Introductory managerial/cost accounting concepts (cost classification, contribution margin, break-even analysis).
This case sits at the intersection of cost accounting and small-business strategy. It asks you to apply cost allocation, bottleneck analysis, and product profitability concepts to a real (disguised) artisan business. If you can price products using accurate cost data and identify capacity constraints, you have the core toolkit this case tests. The broader lesson: even a business with strong demand can fail if it does not understand its own cost structure.
Giberson runs a glass studio making four products. He has plenty of demand (two-week backlog) but is losing money because he does not know what each product costs to make, so he underprices everything. A graduate student, Coates, steps in, tracks costs over six weeks, allocates them to each product, identifies the most profitable line (wrapped tumblers), finds the production bottleneck, and builds a balance sheet so Giberson can make informed pricing and product-mix decisions.
Variable cost
A cost that changes in proportion to the volume of output. In the case, this is the material cost per batch of glass products.
Think of it as: the more you make, the more you spend on raw materials.
Fixed cost
A cost that stays the same regardless of how much you produce within a relevant range. Here, the gas to run the furnace is fixed: it burns whether Giberson makes one piece or fifty.
In simple terms, this means the furnace costs the same to run on a slow day as on a busy one.
Cost allocation
The process of assigning indirect (shared) costs to individual products or cost objects. Coates allocated production costs across Giberson's four product lines to see which ones were profitable.
Think of it as: splitting the shared bill fairly among each product.
Bottleneck
The stage in a production process that limits overall throughput. Coates mapped the flow time for each product and found where the process slowed down.
In simple terms, this means the slowest step in the chain dictates how fast everything else can move.
Product profitability analysis
Comparing the revenue each product generates against its fully allocated costs to determine which products earn money and which do not.
Contribution margin
Revenue minus variable costs for a product. Tells you how much each unit contributes toward covering fixed costs and generating profit. While the case text focuses on total profitability, contribution margin is the underlying concept Coates uses when she compares selling prices to production costs.
Operating cost
The total of all costs required to run the business, including both variable and fixed costs. Coates calculated Giberson's total operating cost to establish a baseline for pricing and cost-reduction decisions.
Balance sheet
A financial statement listing a business's assets, liabilities, and owner's equity at a point in time. Coates created one so Giberson could see his overall financial position, not just product-level profitability.
Giberson is a skilled glassblower with no financial management experience
He has a two-week backlog of orders, so demand is not the issue
He does not know the production cost of any of his four products
He prices by instinct, setting prices too low, which erodes profits
Without intervention, the business faces bankruptcy despite strong demand
Coates, a graduate student, volunteered to help and observed production for six weeks
She separated costs into two categories:
Variable costs: material costs per batch, which change with output volume
Fixed costs: gas to run the furnace, which stays constant regardless of production volume
She tracked these costs at the batch level, then allocated them to each of the four product lines
Coates compared each product's allocated cost against its selling price
The most profitable product: wrapped tumblers
The analysis revealed that some products were being sold below cost
This is the classic managerial accounting insight: you cannot price intelligently without knowing your costs
Coates mapped the flow time for each product through the production process
She identified bottlenecks: stages where production backs up
Understanding the bottleneck tells you where to focus improvement efforts
If the bottleneck is not addressed, adding demand or workers elsewhere will not increase output
Coates calculated total operating cost, giving Giberson a full picture of what it costs to run the studio
She built a balance sheet listing assets and liabilities
This lets Giberson and Coates determine the studio's financial health and plan changes:
Hire additional workers
Drop unprofitable products
Increase production of profitable lines
Adjust prices to cover costs and earn a margin
\text{Total Product Cost} = \text{Direct Materials} + \text{Direct Labour} + \text{Allocated Overhead}\text{Contribution Margin per Unit} = \text{Selling Price} - \text{Variable Cost per Unit}\text{Total Operating Cost} = \text{Total Variable Costs} + \text{Total Fixed Costs}\text{Profit (Loss) per Product} = \text{Revenue from Product} - \text{Fully Allocated Cost of Product}The balance sheet framework also applies:
\text{Assets} = \text{Liabilities} + \text{Owner's Equity}This is exactly how a freelancer, restaurateur, or small manufacturer gets into trouble: they are excellent at their craft but have no system for tracking what each product or service actually costs. The same cost allocation and bottleneck thinking Coates applies here is used in manufacturing plants, consulting firms, and hospitals to decide which services to expand, which to discontinue, and where to invest in capacity.
Bottleneck analysis, in particular, is the foundation of the Theory of Constraints, widely used in operations management. If you have ever wondered why a popular restaurant still struggles financially, the answer is often a version of Giberson's problem: high demand, unknown costs, mispriced menu.
Students often think strong demand guarantees profitability. It does not. Giberson has a two-week backlog and is still heading toward bankruptcy because his prices do not cover his costs.
Students sometimes confuse variable and fixed costs in this case. The gas for the furnace is fixed (it runs regardless of volume), while the materials per batch are variable. Getting this classification wrong will throw off every downstream calculation.
A common mistake is assuming that the most popular product is the most profitable. Popularity (sales volume) and profitability (margin per unit) are separate questions. The wrapped tumblers are most profitable, but they may or may not be the highest-volume seller.
Students sometimes think building a balance sheet is unrelated to the pricing problem. It is not. The balance sheet shows whether the business has enough assets to survive while Giberson implements pricing changes. Without that context, pricing recommendations happen in a vacuum.
Be ready to classify costs as fixed or variable given a scenario description. This is a staple exam question.
Know how to allocate shared costs (like furnace gas) across multiple products using a reasonable allocation base (e.g. furnace time, batches, units produced).
Expect to be asked: "Which product should Giberson produce more of, and why?" The answer requires comparing contribution margins or fully allocated profitability, not just revenue.
Bottleneck identification is frequently tested. If asked "where should Giberson invest to increase output," the answer is always the bottleneck stage, not the most expensive or most visible one.
The balance sheet question tests whether you understand the difference between profitability (income statement) and financial position (balance sheet). Both matter for business survival.
True or False: Giberson's main problem is a lack of customer demand. (False: he has a two-week backlog.)
Fill in the blank: The gas cost to run the furnace is a ______ cost. (Fixed.)
True or False: The most popular product is always the most profitable. (False: volume and margin are different things.)
Fill in the blank: A ______ is the production stage that limits overall throughput. (Bottleneck.)
True or False: A balance sheet shows profitability over a period. (False: it shows financial position at a point in time. Profitability is on the income statement.)
Q: What is the central financial problem facing Giberson's Glass Studio, and why is it surprising given his order volume?
A: Giberson does not know the production cost of each product, so he prices too low. This is surprising because he has a two-week backlog of orders, meaning demand is strong. The problem is not revenue generation but cost recovery: he sells below cost without realising it.
Q: Explain how Coates separated Giberson's costs. Why does this distinction matter for pricing?
A: Coates classified costs as variable (materials per batch, which scale with output) and fixed (furnace gas, which stays constant regardless of volume). This distinction matters because pricing must cover both: variable costs per unit plus a share of fixed costs. Without separating them, you cannot tell which products contribute to covering overhead and which do not.
Q: Which product did Coates identify as most profitable, and what analysis led to that conclusion?
A: Wrapped tumblers. Coates allocated production costs to each of the four product lines and compared allocated costs to selling prices. The wrapped tumblers had the best margin between cost and price.
Q: What is a bottleneck, and why is identifying it important for Giberson's studio?
A: A bottleneck is the production stage with the longest flow time or lowest capacity, limiting overall output. For Giberson, identifying the bottleneck tells him where to focus improvement, because increasing capacity at any other stage will not increase total output.
Q: What strategic options does the case suggest once Giberson has accurate cost and profitability data?
A: Three main options: (1) raise prices on underpriced products so they cover their costs, (2) drop unprofitable products to free up capacity for profitable ones, (3) hire workers or invest in equipment to relieve the bottleneck and increase overall throughput. The balance sheet helps determine whether the business has the financial resources to pursue any of these.
This case connects directly to cost-volume-profit (CVP) analysis, because understanding Giberson's cost structure is the first step toward break-even and target-profit calculations. It also ties into the Theory of Constraints (TOC), since bottleneck identification is the entry point for that framework. If your course covers activity-based costing (ABC), Coates's approach of tracking costs per batch and per product is a simplified version of ABC's logic.
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