Note: This is post #40 in a weekly video series on basic microeconomics.

In an effort to reduce pollution, the government tried two policy prescriptions under the Clean Air Act Amendments of 1990, notes Alex Tabarrok of Marginal Revolution University. The mand and control—mandated that each power plant lower its pollution by a determined amount. However, different firms face different cost curves and, because information is dispersed, policymakers don’t always know those costs. The second policy prescription—tradable pollution permits—empowered firms to use knowledge of their cost curves to buy or sell pollution permits as needed. Guess which worked best?

(If you find the pace of the videos too slow, I’d mend watching them at 1.5 to 2 times the speed. You can adjust the speed at which the video plays by clicking on “Settings” (the gear symbol) and changing “Speed” from normal to 1.25, 1.5 or 2.)

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