第十章、要素市场——劳动市场的供求.doc

第十章、要素市场：劳动市场供求10.1劳动市场需求if ：产品市场、要素市场完全竞争10.1-1边际收益产品MRPL：增加一单位投入所增加的总收益。MRPL=MPL*PL TPL MPL P MRPL PL=MFC=TC/L0 0 0.5 2.51 10 10 0.5 5 2.52 25 15 0.5 7.5 2.53 35 10 0.5 5 2.54 40 5 0.5 2.5 2.55 42 2 0.5 1 2.56 42 0 0.5 0 2.5MRPL和PL dL DL SL PL MRPLMRPL 递减？MPL MRPL10.1-2劳动需求MFC（边际要素成本）=MRPL（边际收益产品）厂商根据PL=MRPL确定劳动数量L？可获最大利润？MPL*P=Q/L*P P=L/Q* PL P=MCMRPL为厂商劳动需求曲线dL ，MRPK、MRPN为dK,dNMRPL= MPL*P=PLMRPK= MPK*P=PK MPK/PK = MPL/PL = MPN/PNMRPN=MPN*P=PN 成本即定产出最大,是否最大？10.1-3派生需求含义：产品需求派生出的要素需求MRPL不变时：D P MRPL*P右移 dL右移 PL （if:L不变）or L （if:PL不变） P不变时：生产率 （管理 or技术 ） MPL MRPL右移 PL （if:L不变）or L （if:PL不变）MRPL dLPL2 PL1 L1 L210.1-4投入的需求弹性eLd=L/L PL/PL影响因素：投入替代性：替代性 eLd 产品需求弹性： ed eLd 投入占总成本中的比重: 比重大 eLd 小调整时间长短: 长 eLd大10.2劳动供给10.2-1供给曲线1.单个厂商面临的SL 2.行业面临的SL行业.SL SLSL水平 ?完全竞争条件厂商对劳动的用量只占整个市场的极小份10.2-2单个劳动供给曲线劳动的机会成本：不劳动=闲暇闲暇的机会成本：工资=商品劳动者在两者之间选择PL 享受闲暇的机会成本 闲暇 SL 替代效应：PL 用劳动替代闲暇。较高PL 工人增加对每种商品购买（包括闲暇） SL 收入效应：高PL 增加闲暇减少劳动。PL SL a以上 收入替代a a以下 替代收入 L10.2-3劳动供给弹性eLS=L/L W/W S 租金： eLS小 P1P0 D1P2 D2 D0 10.3工资决定 L010.3-1工资决定 DL SL Mankiw 补偿性工资： PL2 失业 为抵销不同工作特性产生的工资差别 PL0 最低工资何以会导致失业？PL1 短缺 工资刚性导致失业 减时能否减少失业？10.3-2劳动供给和需求曲线的移动1.劳动需求曲线的移动 if :PL不变产品需求。D产品 DL右移相关要素价格变动。PK DL左移劳动生产率 DL右移2.劳动供给曲线的移动if: W不变其它行业工资率非货币性因素.工作条件、社会地位、兴趣10.4要素市场和产品市场一般均衡if:两种产品 Cloth ,Food；一种要素L劳动市场Food(劳动市场)DL0SL1 Clothes劳动市场要要DL0 DL1 SL1 SL0DL1SL0素W1W0支素W0W1要付 素厂商LL居 民L0 L1 L2L2 L1 L0P DF0 DF1 SF0Dc0 Sc1 Sc0产P1 SF1 P0 Dc1品产P0 P1收 品产入 品消费Q0 Q1 Q2QQ2Q1 Q0支Food市场Clothes市场出产品市场P（P0P1）1.Food市场：DF（DF0DF1）Q（Q0Q1）短期 W（W0W1）需求变动 2.Food劳动市场：DL0（DL0 DL1）Food：0Food市场 L（L0L1）Clothes：00P（P0P1）0Clothes市场3.Clothes市场：Dc（Dc0Dc1）0Q（Q0Q1） W（W0W1）4.Clothes劳动市场：DL（DL0 DL0） L（L0L1） P（P1P0）=05.Food市场：0SF（SF0 SF1） Q（Q1Q2） P（P1P0）=0长期 6.Clothes市场：0Sc（Sc0 Sc1）厂商进出 Q（Q1Q2）=0W（W1W0）7. Food劳动市场 相对W高SL（SL0 SL1）L（L1L2）W（W1W0）8. Clothes劳动市场 相对W低SL（SL0 SL1）L（L1L2）ECONOMICS -PRINCIPLES AND POLICY BAUMOL & BLINDERCASE：THE SODA-PRRICING PROBLEM The managers of one of Americas largest manufacturers of soft drinks became concerned when a rival company introduced a cheaper substitute for one of their leading products.As a result,some of the firms managers advocated a reduction in the price of a six-pack from $1.50 to $1.35.This stimulated a heated debate.It was agreed that the price should be cut if it was not likely to reduce the companys profits.Although some of the managers maintained that the cut made sense because of the demand it would stimulate, others held that the price cut would hurt the company by cutting profit per unit of output. The company had reliable information changes. At this point a group of consultants, including one of the authors of this textbook, was called in to offer their suggestions. We will see how economic analysis enabled them to solve the problem even though the vital demand elasticity figures were unavailable.Our first problem dealt with a firms choice between keeping the price of a brand of soda at$1.50 per six-pack or reducing it to $1.35 when a competitor entered the market. The trouble was that to know what to do, the firm needed to know its demand curve (and hence its marginal revenue curve).However ,the firm did not have enough data to determine the shape of its demand curve. How, then, could a rational decision be made?As we indicated, the debate among the firms managers finally reached agreement on one point: the price should be cut if ,profits were not likely to decline; that is, if marginal profit were not negative. Fortunately, the data needed to determine whether marginal profit was positive were obtainable. Initial annual sales were 10 million units, and the firms engineers maintained emphatically that marginal costs were very close to constant at $1.20 per six-pack over the output range in question. Instead of trying to determine the actual increase in sales that would result from the price cut, the team of consultants decided to try to determine the minimum necessary increase in quantity demanded that would be required to avoid a decrease in profits.It was clear that the firm needed additional revenue at least as great as the additional cost of supplying the added volume, if profits were not to decline. The consultants knew that sales at the initial price of $1.50 per six-pack were $15 million($1.50 per unit times 10 million units). Letting Q represent the (unknown) quantity of six-packs that would be sold at the proposed new price of $1.20 per unit, the added cost amounted to:Added cost =$1.20*(Q-10million).This was to be compared with the added revenue:Added revenue=New revenue-Old revenue=$1.35-$15million.No loss would result from the price change if the added revenue was greater than or equal to the added cost. The minimum Q necessary to avoid a loss therefore was that at which added revenue equaled added cost,or1.35Q-15million=1.2Q-12million, Or0.15Q=3million.This would be true if, and only if, Q, the quantity sold at the lower price, would beQ=20million units.In other words ,this calculation showed that the firm could break even from the 15-cent price reduction only if the quantity of its product demanded rose at least 100 percent(from 10 to 20 million units). Since past experience indicated that such a rise in quantity d