ECO100 - Lecture 9 - F2026

Overview

Matthew Baker applies supply-and-demand diagrams and consumer and producer surplus to compare autarky, free trade, and trade restrictions. Using U.S. T-shirts, airplanes, tariffs, the Jones Act, sugar policy, and fair-trade coffee, he shows how trade creates net gains in the standard model while redistributing benefits, and how tariffs and other interventions can impose costs that are difficult to assess without a credible counterfactual.

Key takeaways

In the T-shirt example, a fall in the U.S. price from $8 to the $5 world price turns the difference between 60 million demanded and 20 million domestically supplied into 40 million imports.
In the standard supply-and-demand model, free trade creates net gains even though it redistributes surplus: U.S. consumers gain from cheaper imports, while domestic producers lose.
For a small country facing a fixed world price, a tariff raises the domestic price by the tariff amount; it reduces imports and creates government revenue but also deadweight loss.
The infant-industry case is difficult to establish because policymakers must identify future winners, account for alternative uses of labor and capital, and compare outcomes with a credible counterfactual.
Trade restrictions can protect one industry while raising input costs for downstream businesses; sugar policy, for example, affects both domestic sugar producers and users such as candy makers.
Fair-trade coffee premiums do not necessarily reach the most disadvantaged workers: the cited Costa Rica research found greater benefits for farm owners and no apparent benefit for unskilled workers.

Chapters

0:00 Exam Review, GradeScope Regrades, and Attendance

Matthew Baker directs students to access exams through GradeScope using their Top Hat email and to email him if they cannot log in.
Students can request regrades through GradeScope, but Baker asks for specific arguments rather than dissatisfaction with a score.
Baker plans to post homework, attendance, and exam results in Brightspace and calculate a running course average.
A new reading and problem set are announced, with the next exam expected in about a month.

5:46 Comparative Advantage: From PPFs to Trade Prices

Baker revisits the PPF example of mountainous Iceland, suited to sheep and wool, and flatter Denmark, suited to wheat.
Specialization and exchange let both islands consume beyond their individual production possibilities frontiers.
The PPF comparison implies different opportunity costs, but does not by itself explain the world price or final quantities traded.
David Ricardo developed the specialization argument; John Stuart Mill later addressed how international prices are determined.

11:36 U.S. T-Shirts: Comparing Autarky with Imports

In the no-trade, or autarky, example, the U.S. T-shirt market sells 40 million shirts annually at $8 each.
Baker assumes overseas suppliers can sell identical T-shirts for a world price of $5.
Because the United States is treated as small relative to the international market, it can buy at the $5 world price without changing it.
At $5, U.S. consumers demand 60 million shirts while domestic producers supply 20 million.

18:44 Import Gains: Consumer Surplus Rises More Than Producer Surplus Falls

At the $5 world price, the gap between 60 million shirts demanded and 20 million produced domestically is filled by 40 million imports.
Before trade, consumer surplus is area A and producer surplus is B plus C; after trade, consumer surplus is A plus B plus D and producer surplus is C.
Consumers gain B plus D, while producers lose B; the additional area D means total surplus rises.
The example identifies both distributional effects and a net efficiency gain from importing at a lower world price.

26:12 U.S. Airplanes: Exporting at a Higher World Price

Baker reverses the case with airplanes, a product the United States can supply to the rest of the world.
The hypothetical domestic market has an autarky outcome of 400 planes at $100 million each.
At an assumed world price of $150 million, U.S. producers supply 700 planes while domestic consumers buy 200, so the remainder is exported.
Producer surplus increases from C to C plus B plus D; consumers lose from the higher price, but the total gains exceed their losses.

31:36 Finding a World Price by Matching Exports and Imports

A two-country model finds an equilibrium price where one country's excess supply equals the other's excess demand.
At prices that do not balance, the importing country's desired purchases do not match the exporting country's available sales.
At the equilibrium price, both countries gain from trade, with total gains represented by adding their respective surplus gains.
Baker notes that full international trade models account for exports and imports across markets and relate to issues such as the U.S. trade deficit.

36:29 How a Tariff Raises the Domestic Price

Under the small-country assumption, a tariff of amount T raises the domestic price from the world price P to P plus T.
Foreign sellers still receive the world-market return after paying the tariff, so the U.S. price must rise enough to cover it.
The higher price reduces domestic quantity demanded and increases domestic quantity supplied, shrinking imports.
Domestic producers benefit from the higher price without paying the import tariff on their own output.

42:58 Tariff Revenue and Deadweight Loss

Tariff revenue equals the tariff per imported unit multiplied by the remaining quantity of imports.
The tariff raises producer surplus and government revenue but reduces consumer surplus.
Two deadweight-loss areas arise because some mutually beneficial consumption and production are lost when imports contract.
The welfare comparison proceeds from no trade to free trade and then to restricted trade, making the counterfactual explicit.

47:17 Why Governments Restrict Trade: Five Common Arguments

Common arguments for tariffs include national security, protecting infant industries, preventing foreign dumping, and preserving domestic jobs.
National-security examples include oil, agriculture, rare-earth metals, and crucial technologies.
A sufficiently high tariff can eliminate imports by pushing the domestic price toward the autarky equilibrium.
Trade quotas can also restrict imports, though their effects and mechanics are more complex than the tariff example.

53:44 Infant-Industry Protection: Investment, Prediction, and Political Risk

The infant-industry argument says temporary protection can give sectors such as semiconductors time to become competitive.
Baker asks why private investors would not fund an industry they expect to become profitable, citing Amazon's growth despite years without profits.
Choosing which industries are strategically important is difficult; Alexander Hamilton supported U.S. manufacturing protection, and East Asian growth offers another contested historical case.
Protection can persist indefinitely, and the evidence is hard to interpret without a controlled comparison of what would have happened otherwise.

57:39 Opportunity Costs, the Jones Act, and U.S. Sugar Protection

Designating an industry as critical draws workers and resources away from alternative uses, creating opportunity costs.
The Jones Act requires shipping between U.S. ports to use U.S.-built ships, which Baker says raises domestic shipping costs.
A U.S. Government Accountability Office assessment of the sugar program found that import limits raise sugar prices and cost the economy about $1 billion per year.
Sugar restrictions benefit domestic producers while imposing costs on consumers and businesses that use sugar, including candy makers such as Hershey.

1:00:26 Dumping Claims and the Limits of Predatory Pricing

The dumping argument holds that foreign firms may sell below cost to drive domestic competitors out and raise prices later.
Baker questions whether this strategy can work in competitive markets, noting that U.S. oil supply can respond quickly when prices rise again.
Research on roughly 4,000 European Union producers involved in anti-dumping cases found that complainant firms often raised markups after cases.
U.S. furniture firms have also used anti-dumping complaints as leverage in negotiations with overseas sellers, according to a Wall Street Journal account.

1:03:50 Job Protection and Fair-Trade Price Floors

Protecting sugar or steel jobs can raise costs for downstream users, such as Hershey or automobile producers, potentially reducing their output and employment.
Supply chains connect many industries, so trade restrictions can preserve some jobs while undermining jobs that depend on imported inputs.
Fair-trade policies that guarantee a price above the market price act like a price floor, encouraging supply beyond the quantity demanded.
A higher guaranteed price also creates a rationing question: in coffee-growing countries, which farms or workers receive access to the premium market?

1:07:23 Fair-Trade Coffee: Who Receives the Premium?

One coffee study finds that competition to obtain fair-trade contracts can dissipate the rents created by premium prices, leaving producers with little overall benefit.
A Costa Rica study covering coffee mills from 1999 to 2014 finds that certification benefits farm owners more than intermediaries.
Unskilled workers, a group fair-trade policies may intend to help, do not appear to benefit in the Costa Rica findings.
Baker emphasizes testing outcomes against the rest of the industry rather than asking only certified participants whether they feel better off.

Summary, takeaways, and chapters were generated by AI from the video's transcript and may contain errors. The video belongs to its creator, Matthew Baker.