劳动市场与AD-AS模型.ppt

第三讲 劳动市场与AD-AS模型,短期分析 凯恩斯定理 总需求视角 没有涉及价格的变动,IS-LM 模型的局限,对总需求增加的中期反应,Higher production requires an increase in employment Higher employment reduces unemployment Lower unemployment puts pressure on wages Higher wages increase production costs and therefore prices Higher prices lead workers to ask for higher wages. Prices and wages (the labor market) adjust over the medium run and influence output,1. 劳动市场基本概念,第一章 劳动市场,失业,国际劳工组织的定义 凡在一定年龄范围内愿意工作且有能力工作而没有工作，并正在寻找工作的人都是失业者。 美国劳工统计局定义 眼下没有工作，正在等待重新被雇佣或者在最近4周里主动地寻找工作的人。美国劳工统计局按月随机抽样来收集，每月大约6万个家庭被访问，询问他们最近的工作情况，调查将16岁以上的成年人分成三类： （1）就业者 （2）失业者 （3）不计入劳动力的所有人：成年人中上学的人、军人、退休在家的、生病不能工作的、干脆不想找工作的。,Current Population Survey Every month, the U.S. Census Bureau surveys 50,000 households to establish the sex, age, and job market status of each member of the household. Working-age population （ Civilian Non-institutional Pop.） Total number of people aged 16 years and over who are not in a jail, hospital, or some other form of institutional care. The working-age population is divided into those in the labor force and those not in the labor force. Labor force The number of people employed plus the number unemployed.,失业率：The percentage of people in the labor force who are unemployed.,两个主要指标,参与率：,A Tour of the Labor Market,U.S. Population 1998 270.2 million Minus: Pop. under 16, -65.0 million Armed forces and Incarcerated Civilian Noninstitutional Pop. 205.2 million Civilian Labor Force 137.6 million Employed 131.4 million Unemployed 6.2 million Out of the Labor Force 67.6 million,The participation rate=,The unemployment rate =,Movements in Unemployment,Small upward trend in the unemployment rate,Observation:,1950s 4.5 1960s 4.7 1970s 6.2 1980s 7.3 1990s 5.9,Cyclical unemployment ：The fluctuating unemployment over the business cycle that increases during a recession and decreases during an expansion. Frictional unemployment： The unemployment that arises from normal labor turnoverfrom people entering and leaving the labor force and from the ongoing creation and destruction of jobs. Structural unemployment is the portion of unemployment that is due to changes in the structure of the economy that result in a significant loss of jobs in certain industries. It arises when changes in technology or international competition change the skills needed to perform jobs or change the locations of jobs.,2. 失业的类型,按照凯恩斯的理论，失业一般分为三种：,摩擦失业：是指在生产过程中由于难以避免的摩擦造成的短期、局部性失业。 Frictional and Structural 自愿失业：是指工人不愿意接受现行工资水平的失业。 Frictional 非自愿失业：是指愿意接受现行工资但仍找不到工作的失业。 Cyclical,Full employment When there is no cyclical unemployment or, equivalently, when all the unemployment is frictional or structural. Natural unemployment rate The unemployment rate at full employment.,3. 古典的劳动市场理论,According to classical economists, the quantity of labor demanded and supplied are brought into equilibrium by rising and falling wage rates. There should be no persistent unemployment above the frictional and structural amount. The classical idea that wages adjust to clear the labor market is consistent with the view that wages respond quickly to price changes.,The labor demand curve illustrates the amount of labor that firms want to employ at each given wage rate.,The labor supply curve illustrates the amount of labor that households want to supply at each given wage rate.,If labor demand decreases, the equilibrium wage will fall. Anyone who wants a job at W1 will have one. There is always full employment in this sense.,Classical economists believe that the labor market always clears.,If wages “stick” at W0 rather than fall to the new equilibrium wage of W* following a shift of demand, the result will be unemployment equal to L0 L1.,古典理论无法解释非自愿失业,4、工资的决定,1. Two Observations:,2. Theories of Wage Determination,Bargaining power Efficiency wages,Workers wages typically exceed their reservation wage Wages depend on labor-market conditions, the lower the u, the higher are wages,Bargaining power depends on:,Efficiency Wages:,Firms themselves may want to pay more than the reservation wage. Because wages above the reservation wage may increase productivity and reduce the turnover rate.,3. Wage determination:,W = Wage （总名义工资） Pe = Expected price level u = The unemployment rate z = Other variables that affect the wage setting,The expected price level, Pe & wages,Workers base their wage request on the purchasing power of their wages or real wage W/P Employers base the wage they pay on the price of the product they sell or the real wage W/P Wage are set in nominal terms, and when they are set, what the relevant price level will be is not yet known.,工资与预期价格而不是实际价格有关，因为：,Higher unemployment reduces bargaining power，forcing workers to accept lower wages. Higher unemployment reduces the efficiency wage.,The unemployment rate, and wages,Unemployment insurance: higher benefits leads to higher wages Structural Economic Change: wages increase when jobs created exceed jobs destroyed,The other factors and wages,5、价格的决定与生产函数,假定劳动是唯一的要素，则,Output： Y = AN N，Employment A，Labor Productivity Assume： A=1 则： Y = N If Y=N， then marginal cost = Wage (W),假定产品市场完全竞争,Price (P) = Marginal Cost Given: Marginal cost = W Then: P=W,P = (1+)W ，Markup of price over cost,假定产品市场不完全竞争,6、自然失业率,1. The wage-setting relation,Assume: Pe = P W=PF(u,z) and dividing by P,The higher the unemployment rate (u), the lower the rate wage,The wage-setting relation:,WS,2. The Price-setting relation:,Recall:,Divide by W:,Invert both sides:,If markup () increases Price (P) increases, given wages (W) Real wage falls,The Price-setting relation:,un The natural rate of unemployment,3. Equilibrium Real Wages, Employment and Unemployment,Labor Market Equilibrium,WS,WS = F(u, Z),Is the natural rate of unemployment “natural”? Scenario: Increase unemployment benefits (z increases),Unemployment Rate, u,Real Wage, W/P,WS = F(u, Z),The increase in Z increases un,Scenario: More stringent antitrust legislation ( decreases),Real Wage, W/P,WS = F(u, Z),The decrease in u reduces un,Unemployment Rate, u,4. The Natural Level of Employment,U = unemployment N = employment L = labor force u = unemployment rate,N = L ( 1-u ),Rearranging for N:,Nn = L ( 1-Un ),5. The Natural Level of Output,Assuming the Production Function: Y = N,At Yn the associated,and the real wage chosen in wage setting equals the real wage implied by price setting.,6. A Summary,Assume: The expected price = actual price level,Then:,Wage setting implies the real wage is inversely related to unemployment The price setting real wage is constant Labor market equilibrium occurs when W/P wage setting = W/P price setting Labor market equilibrium determines the unemployment rate the natural rate of unemployment,7、为什么由此出发？,The Appropriate Time Frame,第二章 AD-AS 模型,1. Aggregate Supply,The aggregate supply relation captures the effects of output on the price level. It is derived from the behavior of wages and prices. Recall the equations for wage and price determination from chapter 6:,一、AS曲线的推导,Step 1: Eliminate the nominal wage from:,and, then:,In words, the price level depends on the expected price level and the unemployment rate. We assume that and z are constant.,Step 2: Express the unemployment rate in terms of output:,Therefore, for a given labor force, the higher is output, the lower is the unemployment rate.,Step 3: Replace the unemployment rate in the equation obtained in step one:,In words, the price level depends on the expected price level, Pe, and the level of output, Y (and also , z, and L, but we take those as constant here).,上式即AS 曲线,二、AS曲线的特征,The AS curve goes through point A, where Y = Yn and P = Pe. This property has two implications: When Y Yn, P Pe. When Y Yn, P Pe. An increase in the expected price level leads, one for one, to an increase in the actual price level. Then shifts the AS curve up, This effect works through wages:,YNuWC P,The AS curve is upward sloping. An increase in output leads to an increase in the price level.,Given the expected price level, an increase in output leads to an increase in the price level. If output is equal to the natural level of output, the price level is equal to the expected price level.,The Aggregate Supply Curve,An increase in the expected price level shifts the aggregate supply curve up.,The Effect of an Increase in the Expected Price Level on the Aggregate Supply Curve,2. Aggregate Demand,The aggregate demand relation captures the effect of the price level on output. It is derived from the equilibrium conditions in the goods and financial markets.,一、AD曲线的推导,An increase in the price level leads to a decrease in output.,The Derivation of the Aggregate Demand Curve,Changes in monetary or fiscal policyor more generally in any variable, other than the price level, that shift the IS or the LM curvesshift the aggregate demand curve.,二、AD曲线的移动,An increase in government spending increases output at a given price level, shifting the aggregate demand curve to the right. A decrease in nominal money decreases output at a given price level, shifting the aggregate demand curve to the left.,Shifts of the Aggregate Demand Curve,3. Equilibrium in the Short Run and in the Medium Run,Equilibrium depends on the value of Pe. The value of Pe determines the position of the aggregate supply curve, and the position of the AS curve affects the equilibrium.,一、短期均衡,The equilibrium is given by the intersection of the aggregate supply curve and the aggregate demand curve. At point A, the labor market, the goods market, and financial markets are all in equilibrium.,The Short Run Equilibrium,二、由短期到长期,At point A,Wage setters will revise upward their expectations of the future price level. This will cause the AS curve to shift upward. Expectation of a higher price level also leads to a higher nominal wage, which in turn leads to a higher price level.,From the Short Run to the Medium Run,The adjustment ends once . Wage setters no longer have a reason to change their expectations. In the medium run, output returns to the natural level of output.,From the Short Run to the Medium Run,If output is above the natural level of output, the AS curve shifts up over time, until output has decreased back to the natural level of output.,The Adjustment of Output over Time,4. The Effects of a Monetary Expansion,In the aggregate demand equation, we can see that an increase in nominal money, M, leads to an increase in the real money stock, M/P, leading to an increase in output. The aggregate demand curve shifts to the right.,The Dynamics of Adjustment,The increase in the nominal money stock causes the aggregate demand curve to shift to the right. In the short run, output and the price level increase. The difference between Y and Yn sets in motion the adjustment of price expectations.,The Dynamic Effects of a Monetary Expansion,In the medium run, the AS curve shifts to AS and the economy returns to equilibrium at Yn. The increase in prices is proportional to the increase in the nominal money stock.,The Dynamics of Adjustment,A monetary expansion leads to an increase in output in the short run, but has no effect on output in the medium run.,The Dynamic Effects of a Monetary Expansion,Going Behinds the Scenes,The impact of a monetary expansion on the interest rate can be illustrated by the IS-LM model. The short-run effect of the monetary expansion is to shift the LM curve down. The interest rate is lower, output is higher.,Going Behinds the Scenes,If the price level did not increase, the shift in the LM curve would be largerto LM.,Going Behinds the Scenes,Over time, the price level increases, the real money stock decreases and the LM curve returns to where it was before the increase in nominal money. In the medium run, the real money stock and the interest rate remain unchanged.,Going Behinds the Scenes,The increase in nominal money initially shifts the LM curve down, decreasing the interest rate and increasing output. Over time, the price level increases, shifting the LM curve back up until output is back at the natural level of output.,The Dynamic Effects of a Monetary Expansion on Output and the Interest Rate,The Neutrality of Money,Over time, the price level increases, and the effects of a monetary expansion on output and on the interest rate disappear. The neutrality of money refers to the fact that an increase in the nominal money stock has no effect on output or the interest rate in the medium run. The increase in the nominal money stock is completely absorbed by an increase in the price level.,5. A Decrease in the Budget Deficit,The Dynamic Effects of a Decrease in the Budget Deficit,A decrease in the budget deficit leads initially to a decrease in output. Over time, output returns to the natural level of output.,Deficit Reduction, Output, and the Interest Rate,Since the price level declines in response to the decrease in output, the real money stock increases. This causes a shift of the LM curve to LM. Both output and the interest rate are lower than before the fiscal contraction.,The LM curve continues to shift down until output is back to to the natural level of output. The interest rate is lower than it was before deficit reduction.,Deficit reduction leads in the short run to a decrease in output and to a decrease in the interest rate. In the medium run, output returns to its natural level, while the interest rate declines further.,The Dynamic Effects of a Decrease in the Budget Deficit on Output and the Interest Rate,Deficit Reduction, Output, and the Interest Rate,The composition of output is different than it was before deficit reduction.,Income and taxes remain unchanged, thus, consumption is the same as before. Government spending is lower than before; therefore, investment must be higher than before deficit reductionhigher by an amount exactly equal to the decrease in G. In the medium run, budget deficit reduction leads to a decrease in the interest rate and an increase in investment.,6. Changes in the Price of Oil,The Price of Crude Petroleum, 1960-2001,There was two sharp increases in the relative price of oil in the 1970s, followed by a decrease in the 1980s and the 1990s.,Effects on the Natural Rate of Unemployment,The higher price of oil causes an increase in the markup and a downward shift of the price-setting line.,The Effects of an Increase in the Price of