曼昆微观经济学原理 第六章 PPT

Supply, Demand, and Government Policies,Macroeconomics,P R I N C I P L E S O F,N. Gregory Mankiw,Premium PowerPoint Slides by Ron Cronovich,6,In this chapter, look for the answers to these questions:,What are price ceilings and price floors? What are some examples of each? How do price ceilings and price floors affect market outcomes? How do taxes affect market outcomes? How do the effects depend on whether the tax is imposed on buyers or sellers? What is the incidence of a tax? What determines the incidence?,1,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,2,Government Policies That Alter the Private Market Outcome,Price controlsPrice ceiling: a legal maximum on the price of a good or service Example: rent control Price floor: a legal minimum on the price of a good or service Example: minimum wage TaxesThe govt can make buyers or sellers pay a specific amount on each unit bought/sold.,We will use the supply/demand model to see how each policy affects the market outcome (the price buyers pay, the price sellers receive, and eqm quantity).,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,3,EXAMPLE 1: The Market for Apartments,Eqm w/o price controls,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,4,How Price Ceilings Affect Market Outcomes,A price ceiling above the eqm price is not binding has no effect on the market outcome.,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,5,How Price Ceilings Affect Market Outcomes,The eqm price ($800) is above the ceiling and therefore illegal.The ceiling is a binding constraint on the price, causes a shortage.,$800,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,6,How Price Ceilings Affect Market Outcomes,In the long run, supply and demand are more price-elastic. So, the shortage is larger.,$800,150,450,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,7,Shortages and Rationing,With a shortage, sellers must ration the goods among buyers. Some rationing mechanisms: (1) Long lines (2) Discrimination according to sellers biasesThese mechanisms are often unfair, and inefficient: the goods do not necessarily go to the buyers who value them most highly. In contrast, when prices are not controlled, the rationing mechanism is efficient (the goods go to the buyers that value them most highly) and impersonal (and thus fair).,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,8,EXAMPLE 2: The Market for Unskilled Labor,Eqm w/o price controls,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,9,How Price Floors Affect Market Outcomes,A price floor below the eqm price is not binding has no effect on the market outcome.,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,10,How Price Floors Affect Market Outcomes,The eqm wage ($4) is below the floor and therefore illegal.The floor is a binding constraint on the wage, causes a surplus (i.e., unemployment).,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,11,Min wage laws do not affect highly skilled workers. They do affect teen workers. Studies: A 10% increase in the min wage raises teen unemployment by 1-3%.,The Minimum Wage,A C T I V E L E A R N I N G 1 Price controls,Determine effects of:A. $90 price ceilingB.$90 price floorC.$120 price floor,12,A C T I V E L E A R N I N G 1 A. $90 price ceiling,The price falls to $90. Buyers demand 120 rooms, sellers supply 90, leaving a shortage.,13,A C T I V E L E A R N I N G 1 B. $90 price floor,Eqm price is above the floor, so floor is not binding. P = $100, Q = 100 rooms.,Price floor,14,A C T I V E L E A R N I N G 1 C. $120 price floor,The price rises to $120. Buyers demand 60 rooms, sellers supply 120, causing a surplus.,15,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,16,Evaluating Price Controls,Recall one of the Ten Principles from Chapter 1: Markets are usually a good way to organize economic activity.,Prices are the signals that guide the allocation of societys resources. This allocation is altered when policymakers restrict prices. Price controls often intended to help the poor, but often hurt more than help.,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,17,Taxes,The govt levies taxes on many goods & services to raise revenue to pay for national defense, public schools, etc. The govt can make buyers or sellers pay the tax. The tax can be a % of the goods price, or a specific amount for each unit sold. For simplicity, we analyze per-unit taxes only.,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,18,EXAMPLE 3: The Market for Pizza,Eqm w/o tax,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,19,A Tax on Buyers,The price buyers pay is now $1.50 higher than the market price P. P would have to fallby $1.50 to makebuyers willing to buy same Q as before. E.g., if P falls from $10.00 to $8.50,buyers still willing topurchase 500 pizzas.,Effects of a $1.50 per unit tax on buyers,Hence, a tax on buyers shifts the D curve down by the amount of the tax.,SUPPLY, DEMAND, AND GOVERNMENT POLICIES,20,A Tax on Buyers,Effects of a $1.50 per unit tax on buyers,