Week 15 Business Case Workshop: Who Builds, Who Repairs, and How Far Abroad?

Part 1 — The Big Picture

This week you watched two illustrative islands gain from trade even though East Island made more of both goods: a fish cost East 2 fruit and West 4 fruit, so East leaned into fish, West into fruit, and the world went from 50 fruit and 20 fish to 52 and 24. You also learned that the importer of record owes a tariff at the border and that a firm climbs the entry ladder with risk and control rising together. In this workshop you use the same tools inside one small business, an illustrative two-partner bike shop: you decide who should build frames and who should do repairs, price a tariff on imported tubing, read a cross-border order and a balance sheet, and recommend how the shop should first sell abroad. Finally, you check a chatbot's analysis of the same case and correct it by hand.

Time budget: Plan for about 90 minutes.

Part 2 — The Task

Guiding question: Who in the shop should build frames and who should do repairs, what do the tubing tariff and the cross-border order do to the shop's numbers and its balance sheet, and which rung of the entry ladder should the shop use first once you weigh risk, control, the people the choice touches, and the strongest case against your choice?

Workshop data: An illustrative two-partner bike shop's week, import, and export order

Source: The two partners' daily output, a week's working days, an imported tubing order and its tariff rate, a cross-border frame order with its price and cost, and the shop's balance sheet before and after a new loan, written for this workshop and printed in full in Part 4; the shop is not real data and describes no real business, place, or person.

• Rows: one shop's figures; the output table in Part 4 has 2 rows, the week-plan table has 3 rows, the border-and-order table has 9 rows, and the entry-ladder table has 6 rows
• Columns: each partner's daily output and opportunity costs; each week plan's frames and repairs; each line of the import, the order, and the balance sheet with its dollars; each rung with its money at risk and control
• Decision: which rung of the entry ladder the shop should use first to sell frames across the border, weighing risk, control, and the people the choice touches

Part 3 — Materials & Procedure

Tools and materials

• A free spreadsheet (Google Sheets, or any free spreadsheet) for every computation; the SBA's free planning pages and SCORE's free templates for the plan; the SEC's EDGAR full-text search and investor.gov for what a real filing and a real security are; Census, BEA, and BLS data tables for real figures; and one approved chatbot used as a pair consultant whose numbers the student recomputes before trusting them

Ways of working

• analyze-the-case
• run-the-numbers
• recommend-and-defend

Procedure

1. Open a blank sheet in a free spreadsheet. In A1 type Partner, in B1 Frames per day, and in C1 Repairs per day. In A2 type Senior builder with 6 in B2 and 12 in C2; in A3 type Newer mechanic with 2 in B3 and 10 in C3. Tool: A free spreadsheet (Google Sheets, or any free spreadsheet) for every computation; the SBA's free planning pages and SCORE's free templates for the plan; the SEC's EDGAR full-text search and investor.gov for what a real filing and a real security are; Census, BEA, and BLS data tables for real figures; and one approved chatbot used as a pair consultant whose numbers the student recomputes before trusting them. Check: Rows 2 and 3 hold each partner's output for one day.
2. In D1 type Cost of a frame in repairs and in D2 type =C2/B2, then copy it to D3. In E1 type Cost of a repair in frames and in E2 type =B2/C2, then copy it to E3. Fill the four cost cells of the output table in Part 4 from these cells. Tool: A free spreadsheet (Google Sheets, or any free spreadsheet) for every computation; the SBA's free planning pages and SCORE's free templates for the plan; the SEC's EDGAR full-text search and investor.gov for what a real filing and a real security are; Census, BEA, and BLS data tables for real figures; and one approved chatbot used as a pair consultant whose numbers the student recomputes before trusting them. Check: Column D shows each partner's repairs given up per frame and column E each partner's frames given up per repair; the smaller number in each column marks the comparative advantage.
3. For the even split, where each partner spends 2 days on frames and 2 on repairs, type =2*B2 and =2*C2 for the senior builder and =2*B3 and =2*C3 for the newer mechanic, and add the two partners. For the specialized plan, where the senior builder spends 3 days on frames and 1 on repairs and the newer mechanic spends all 4 days on repairs, type =3*B2, =1*C2, and =4*C3, and add the shop's totals. Tool: A free spreadsheet (Google Sheets, or any free spreadsheet) for every computation; the SBA's free planning pages and SCORE's free templates for the plan; the SEC's EDGAR full-text search and investor.gov for what a real filing and a real security are; Census, BEA, and BLS data tables for real figures; and one approved chatbot used as a pair consultant whose numbers the student recomputes before trusting them. Check: The week-plan table in Part 4 has frames and repairs for each partner and the shop under both plans.
4. In a new block type the tubing order, 9000, and the tariff rate, 0.05, and multiply them for the duty. Type the frame order, 30 frames at 400 dollars, and the cost of 250 dollars a frame, and compute the order's revenue, its cost, and its gross profit. Tool: A free spreadsheet (Google Sheets, or any free spreadsheet) for every computation; the SBA's free planning pages and SCORE's free templates for the plan; the SEC's EDGAR full-text search and investor.gov for what a real filing and a real security are; Census, BEA, and BLS data tables for real figures; and one approved chatbot used as a pair consultant whose numbers the student recomputes before trusting them. Check: The border-and-order table's duty, revenue, cost, and gross-profit cells are filled, each from a formula you can see.
5. Add the balance sheet before the order: cash 5,000, inventory 3,000, and equipment 12,000 against a loan of 6,000 and owner's equity of 14,000. Then add the 9,450-dollar new loan to both inventory and liabilities, total each side, and check that assets equal liabilities plus owners' equity. Tool: A free spreadsheet (Google Sheets, or any free spreadsheet) for every computation; the SBA's free planning pages and SCORE's free templates for the plan; the SEC's EDGAR full-text search and investor.gov for what a real filing and a real security are; Census, BEA, and BLS data tables for real figures; and one approved chatbot used as a pair consultant whose numbers the student recomputes before trusting them. Check: Both sides of the balance sheet after the new loan show the same total.
6. Fill the entry-ladder table in Part 4 by writing, for each rung, how much money the shop would put at risk and how much control it would keep, in your own words, then mark the rung you would choose first. Tool: A free spreadsheet (Google Sheets, or any free spreadsheet) for every computation; the SBA's free planning pages and SCORE's free templates for the plan; the SEC's EDGAR full-text search and investor.gov for what a real filing and a real security are; Census, BEA, and BLS data tables for real figures; and one approved chatbot used as a pair consultant whose numbers the student recomputes before trusting them. Check: Each of the six rungs has a risk note and a control note, and one rung is marked as your choice.

Fallback route

When to use it: Use this route if a spreadsheet will not open or a formula will not run.

Work every step by hand from the figures printed in Part 4: divide each partner's output for the four opportunity costs, multiply days by daily output for both week plans, multiply the tubing by the tariff rate, multiply the frame order by the price and by the cost, and add each side of the balance sheet after the loan. Complete every analysis question and the critique step, and submit the same items for equal credit.

This route earns the same credit as the primary route.

Part 4 — The Scaffold

Find each partner's opportunity costs, because comparative advantage goes to the lower cost, not to whoever makes more.

Student scaffold table 1

Partner	Frames per day	Repairs per day	Cost of one frame, in repairs	Cost of one repair, in frames
Senior builder	6	12
Newer mechanic	2	10

Compare the shop's week under an even split and under the specialized plan, because specializing only pays if the shop ends with at least as much of each kind of work.

Student scaffold table 2

Who	Frames, even split	Repairs, even split	Frames, specialized plan	Repairs, specialized plan
Senior builder
Newer mechanic
Shop total

Price the border and the order, and check the balance sheet after the new loan, because a cross-border step changes both the shop's profit and what it owes.

Student scaffold table 3

Line	Dollars or answer
Imported tubing	9,000
Tariff rate	5 percent
Duty owed at the border
Who owes the duty at the border
Frame order revenue (30 frames at 400 dollars)
Frame order cost (30 frames at 250 dollars)
Frame order gross profit
Total assets after the new 9,450-dollar loan
Total liabilities plus owner's equity after the new loan

Place each way into a foreign market by risk and control, because the ladder is a menu and the right rung depends on the case.

Student scaffold table 4

Rung	Money the shop puts at risk	Control the shop keeps
Exporting through the distributor
Licensing the frame design
Franchising a shop under its name
Contract manufacturing abroad
A joint venture with a foreign partner
Direct foreign investment in a workshop abroad

Part 5 — Analysis Questions

1. Write the arithmetic for each partner's cost of a frame in repairs and cost of a repair in frames, say who has the absolute advantage in each task and who has the comparative advantage in each, and give the shop's frames and repairs for a week under both plans.
2. Using your border-and-order table, find the duty owed on the tubing and say who owes it at the border; then give two readings of who might bear that cost afterward, and say why the course leaves that question open.
3. Explain why the frame order's revenue is not its profit, and show that the balance sheet still balances after the new loan, saying why the loan raises both sides together.
4. Sort two pieces of news into a SWOT for the shop, the senior builder's skill and a bike shop across the border that wants to stock the frames, and say which one is a trade force from outside the business.
5. Choose one: (a) recommend which rung of the entry ladder the shop should use first in 5–8 sentences, using your risk and control notes, naming one person or group who gives something up, the strongest case for another rung, and the fact that would change your mind; or (b) argue for the rung you would least choose as strongly as you can in 5–8 sentences, then say in two sentences why you still hold your view or why you changed it.
6. Name one way this classroom case is simpler than a real shop deciding to trade across a border, such as shipping costs, a partner who cannot switch tasks overnight, or a cost that changes with the size of the order, and say how it could change your recommendation.

Part 6 — AI-Critique Moment

Choose one equal-credit critique route. Route A: ask an approved AI tool to critique your completed work, then check its response against your own evidence. Route B is the no-AI equivalent printed below.

Approved tools: Claude, Gemini, ChatGPT, Grok, Microsoft Copilot.

Prompt to paste:

I've pasted my completed Week 15 Business Case Workshop tables above. They describe an illustrative two-partner bike shop, invented for a class activity, not a real business. In one day the senior builder can build 6 frames or do 12 repairs, and the newer mechanic can build 2 frames or do 10 repairs; each works 4 days a week. The shop imports 9,000 dollars of steel tubing, and a 5 percent tariff applies at the border. A distributor across the border offers to buy 30 frames at 400 dollars each, and each frame costs the shop 250 dollars in tubing, parts, and duty. Before the order, the shop has cash of 5,000 dollars, inventory of 3,000 dollars, and equipment of 12,000 dollars, with a loan of 6,000 dollars and owner's equity of 14,000 dollars; it borrows another 9,450 dollars to pay for the tubing and the duty. Please do nine things. First, tell me which partner should build frames and which should do repairs, with each opportunity cost. Second, tell me how much the frame order earns the shop in profit. Third, draw the balance sheet after the new loan. Fourth, tell me who pays the tariff at the border. Fifth, sort these into a SWOT: the senior builder's skill, and a bike shop across the border that wants to stock the frames. Sixth, tell me what share of small bike shops that start exporting succeed. Seventh, compare the shop's export plan with a large international bicycle company's export sales. Eighth, tell me exactly which customs forms and tariff classification the shop should file for the tubing. Ninth, recommend how the shop should first sell abroad, as a short plan.

Test the response for these likely failures:

• Chatbots often flip an opportunity-cost ratio, saying a frame costs the senior builder 12 ÷ 6 = 0.5 repairs or giving the frames to whoever builds more of them without comparing costs.
• Chatbots often call the order's 30 × 400 = 12,000 dollars the shop's profit.
• Asked for the balance sheet after the new loan, chatbots often add the 9,450 dollars of tubing and duty to inventory but leave the loan at 6,000 dollars, so assets of 29,450 sit beside liabilities and equity of 20,000.
• Chatbots often list the bike shop across the border among the shop's strengths, because its interest is good news.
• Asked what share of small bike shops that start exporting succeed, chatbots often give a confident percentage with no source or year.
• Asked to compare with a large international bicycle company, chatbots often quote that company's export sales or history with no source.
• Chatbots often name the exact customs forms and tariff classification the shop should file, as if they knew the goods, the port, and the shop's full situation.
• Chatbots often recommend a joint venture or a factory abroad because it means more control, never mentioning the money at risk, the newer mechanic's workload, or the case for exporting first.
• Chatbots often write a plan of stock phrases such as research the market, build the brand, and scale globally that uses none of the case's numbers.

Write 3–5 sentences naming one thing the chatbot got right and at least two places it went wrong or overreached, quoting its words and correcting each with evidence from your own tables or this week's chapter.

Equivalent route (no AI required)

No AI account is required for this workshop. Instead of the chatbot, critique this flawed analysis, printed here in full: "The senior builder makes more frames and more repairs, so the senior builder should do both jobs and the newer mechanic has no comparative advantage; a frame costs the senior builder 12 ÷ 6 = 0.5 repairs. The frame order earns 30 × 400 = 12,000 dollars of profit. The foreign tubing maker pays the tariff at the border. After the new loan, the balance sheet shows assets of 29,450 dollars against liabilities of 6,000 and owner's equity of 14,000. The bike shop across the border that wants the frames is the shop's biggest strength. About 60 percent of small bike shops that start exporting succeed. A large international bicycle company exports most of its frames, so the shop should copy it. The shop should file its tubing under a specific tariff code on a particular customs form. The shop should open its own workshop abroad, because more control is always better, and nothing else matters. To succeed, the shop should research the market, build its brand, and scale globally." Mark it up: quote each flawed sentence, name what is wrong (an opportunity cost computed wrong or comparative advantage given to whoever makes more, revenue presented as profit, the wrong party named as owing the duty, a balance sheet that does not balance, an outside opportunity filed as a strength, a figure with no source, an unsourced claim about a real firm, confident customs advice for one shop, a recommendation that ignores a stakeholder and the counter-case, or boilerplate that ignores the case), cite the evidence from your tables or the chapter, and write a corrected version of each sentence. This route assesses the same objectives (Objective 8 and Objective 1), takes about the same time as the chatbot critique, about 20 minutes within the workshop, and is scored by the same criteria for the same credit. Submit the marked-up analysis in place of the chatbot report and share link.

Part 7 — What to Submit

• All four completed scaffold tables
• Written answers to all six analysis questions, including your recommendation
• The chatbot critique report with its share link, or the equivalent route's marked-up flawed analysis

Deliverable:

A short Business Case Workshop report on an illustrative two-partner bike shop: four completed tables (the partners' opportunity costs, the week under both plans, the border and the order with the balance sheet after the loan, and the entry ladder by risk and control), written answers to six analysis questions including a weighed recommendation, and a critique of a chatbot's analysis of the same case, or, on the equivalent route, a marked-up correction of the printed flawed analysis. Submit in any accessible file type or as a link; a recorded response may be submitted as audio or video with a transcript, or as text. Choose a written, recorded, or visual form for your answers; every form is graded by the same scoring criteria.

Rubric

The rubric below shows how each submitted part is evaluated; bands are full, partial, or none.

Workshop evaluation criteria

Criterion	Full	Partial	None
Opportunity costs and the specialized plan	All four opportunity costs are found with the task given up on top, absolute and comparative advantage are kept apart for both tasks, and both week plans are totalled with the arithmetic shown.	Most costs and totals are shown, but one ratio is flipped, one total is off, or comparative advantage is given to whoever makes more.	No opportunity costs or week totals are shown, or figures appear with no arithmetic behind them.
The border, the order, and the balance sheet	The duty is computed and placed on the importer of record with the later sharing left open, the order's revenue is kept apart from its gross profit, and the balance sheet after the loan balances with the check written out.	Most of these are present, but the duty is placed on the foreign seller, revenue is called profit, or the sheet does not balance.	No duty, order figures, or balance-sheet check is submitted.
Filing trade news in the SWOT	The senior builder's skill is filed as a strength and the bike shop across the border as an opportunity, with the inside-or-outside reason stated for each.	Both items are placed, but one is misfiled or the reason is missing.	No SWOT placement is submitted.
A weighed entry recommendation	The recommendation or the argued other side rests on the risk and control notes, names a person or group who gives something up, states the strongest case for another rung, and says what would change the decision.	A rung is chosen and tied to some case facts, but the case for another rung, the person or group who gives something up, or what would change the decision is missing.	No recommendation is made, or it ignores the case's facts.
Catching and correcting the AI slip	On either route, the chatbot's words or the printed flawed analysis are quoted and at least two errors are corrected with evidence from the tables or the chapter, and any invented figure or advice is flagged.	On either route, one error is caught and corrected, or errors are named without the corrected evidence.	On either route, no critique is submitted, or the output is pasted without any checked correction.

Quality Gate

• Every opportunity cost, week total, duty, revenue, cost, gross profit, and balance-sheet figure comes from your own arithmetic on the printed figures, never from a chatbot.
• Each opportunity cost puts the task given up on top, and comparative advantage goes to the lower cost, not to whoever makes more.
• The balance sheet after the new loan satisfies assets = liabilities + owners' equity to the dollar, with the check written out, and the order's revenue is kept apart from its profit.
• The importer of record is named as owing the duty at the border, who bears it afterward is left open, and nothing is offered as customs, tax, or legal advice for a real shop; no statistic, real-company figure, or tariff rate is invented.
• The recommendation names at least one person or group who gives something up, the strongest case for another rung, and what would change the answer.
• The critique quotes the chatbot or the flawed analysis and corrects at least two errors with evidence from your tables or the chapter.