Public goods, and costs or benefits that fall on others
Grade 12 Social Studies Worksheet - Challenge Me

Circle the best answer.
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Cards A to C on limiting pollution (card A is exact; cards B and C are made up). Card A, "The Acid Rain Program". Who made it: the Environmental Protection Agency (epa.gov), read November 14, 2026. Excerpt 1: "The ARP was the first national cap and trade program in the country" Excerpt 2: "introduced a system of allowance trading that uses market-based incentives to reduce pollution." Excerpt 3: "the final 2010 SO2 cap set at 8.95 million tons, a level of about one-half of the emissions from the power sector in 1980." Card B, "Two plants (made up)". Who made it: written for this sheet. Summary in our words, not a quotation: Plant X and Plant Y each now emit 100 tons a year. A cap limits the two together to 160 tons. Cutting a ton costs Plant X $50 and costs Plant Y $200. Plant Y stands next to a town. Plant X is far from any town. Under Rule 1 each plant must cut 20 tons. Under Rule 2 each plant gets allowances for 80 tons and may sell or buy allowances. Card C, "A critic (made up)". Who made it: written for this sheet. Summary in our words, not a quotation: Trading lets a plant buy the right to pollute, so a trading plan allows more pollution than a fixed rule.
Pia compares Rule 1 and Rule 2 on card B. What does each cost the two plants in cutting, and how much do they emit?
- Rule 1 costs $2,000 and Rule 2 costs $5,000, and both hold the total to 160 tons
- Rule 1 costs $5,000 and Rule 2 costs $2,000, but Rule 2 lets the total rise above 160 tons
- Rule 1 costs $5,000 and Rule 2 costs $2,000, and both hold the total to 160 tons
- Rule 1 costs $5,000 and Rule 2 costs $2,000, and Rule 2 holds the total to 120 tons
Esme tests the critic's claim on card C against card B. What is the verdict?
- Right: trading plans cost less, which shows that they allow more pollution than a fixed rule
- Wrong: trading lets both plants emit 80 tons each, so no plant emits more than under Rule 1
- Right: Plant Y can buy allowances, so Y emits more than under Rule 1 and the total is higher
- Wrong on the total: the cap holds emissions at 160 tons either way; trading changes who cuts
Someone says Rule 2 is better in every way. What is Tala's strongest objection from card B?
- Rule 2 saves nothing, since Plant Y pays Plant X what the cut would have cost Plant Y
- Plant X must cut 40 tons, which costs it $2,000, so the cost to Plant X is very large
- Rule 2 lets the total rise above 160 tons, since plants can buy extra allowances from X
- The cap limits total tons, not where: Plant Y can keep emitting 100 tons next to a town
Milo asks what evidence would best test a cap and trade plan like the Acid Rain Program. What is missing?
- Yearly emissions against the cap, and whether harm near the heaviest emitters grew
- How many allowances the EPA gave out in 1980, before the program had even begun
- The cost of cutting a ton at one plant, which card B already gives for both plants
- The market price of allowances in a single week, to compare with $50 and $200 a ton
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Cards A to C on a tax on a polluting good (all made up). Card A, "The good and the tax (made up)". Who made it: written for this sheet. Summary in our words, not a quotation: The good sells for $4.00 a unit. A tax of $1.00 a unit is added. Demand has an elasticity of 0.4 and supply an elasticity of 1.2, both written as positive numbers. In a simple model, buyers bear the share Es ÷ (Ed + Es) of a tax, and sellers bear the rest. A percent fall in quantity equals the elasticity of demand times the percent rise in the price buyers pay. Card B, "Two households (made up)". Who made it: written for this sheet. Table, columns Household | Share of income spent on the good: low income | 3 percent; high income | 1 percent. Card C, "A claim (made up)". Who made it: written for this sheet. Summary in our words, not a quotation: A tax that adds $1.00 to a $4.00 good will cut its use, and its pollution, by a quarter. Everyone pays the same tax on each unit, so it is fair.
Jun applies the share rule on card A. What happens to the price buyers pay and to the quantity?
- Buyers pay $1.00 more, up 25 percent, and quantity falls 10 percent
- Buyers pay about $0.25 more, up about 6 percent, and quantity falls about 2.5 percent
- Buyers pay about $0.75 more, up about 19 percent, and quantity falls about 7.5 percent
- Buyers pay about $0.75 more, up about 19 percent, and quantity falls about 19 percent
Ren tests the first half of the claim on card C against card A. What is the verdict?
- Overstated: the tax would cut use by half, since the supply elasticity is 1.2 for sellers
- Overstated: the buyers' price rises about 19 percent, so quantity falls only about 7.5 percent
- Right: a $1.00 tax on a $4.00 good is a 25 percent rise, so use falls by a quarter too
- Wrong: the tax does not change use, since demand is inelastic and buyers keep buying
Use this
Cards A to D on a shared lake (cards A, B and D are made up; card C is a citation). Card A, "A lake fishery (made up)". Who made it: written for this sheet. Table, columns Boats | Total catch (tons): 1 | 30; 2 | 50; 3 | 60; 4 | 64. Each boat costs the equivalent of 18 tons of fish a season to run. Card B, "Open access (in our words)". Who made it: written for this sheet. Summary in our words, not a quotation: A new boat enters while the catch per boat is at least the cost of running a boat. Nobody can be kept off the lake. Card C, "Elinor Ostrom". Who made it: the Royal Swedish Academy of Sciences, 2009. Excerpt: "for her analysis of economic governance, especially the commons". She shared the 2009 prize with Oliver Williamson. Her best-known book, Governing the Commons (1990), described groups that managed shared resources by rules they made themselves. Card D, "A claim (made up)". Who made it: written for this sheet. Summary in our words, not a quotation: A shared resource is ruined unless it is privatized or run by the state.
Kira applies card B to card A. How many boats enter, how many would be best, and how does the catch net of cost compare?
- 3 boats enter, and 3 is the right number, since the net catch of 6 tons is above zero
- 2 boats enter, but 3 would leave a net catch of 14 tons against 6 for two
- 4 boats enter, and 3 would leave a net catch of 6 tons against −8 for four
- 3 boats enter, but 2 would leave a net catch of 14 tons against 6 for three boats
A reader says open access is fine, since the fish are caught either way. What is Zee's strongest objection?
- The 3rd boat adds just 10 tons for a cost of 18, and it lowers the catch per boat
- The lake is public, so fish taken by one boat cannot harm the others
- The 2nd boat adds 20 tons, which is more than the 18 it costs, so it should stay out
- The 4th boat adds 4 tons, so a 4th boat will enter and lower the net catch further
Ari tests the claim on card D against card C. What is the verdict?
- Strong: the lake on card A is ruined with 3 boats, which supports the claim for commons in general
- Weak: card C describes groups that managed commons by their own rules, so ruin is not certain
- Weak: card C says privatizing a resource works, so the state has no part to play in it
- Strong: card C gives a prize, which shows that economists accept the claim as sound
Milo asks what evidence would best test whether self-made group rules protect a commons. What is missing?
- Whether Ostrom shared the prize with Oliver Williamson, which card C already says
- How many fish a boat catches in a season, which card A already gives for the made-up lake
- How many self-ruled groups kept their resource, against similar open-access groups
- What a boat costs to run, since that decides whether groups can afford to make rules