TopicstobeDiscussed衡量成本

1、Chapter 7 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本2 Topics to be Discussed l衡量成本? l短期成本 l长期成本 l长期和短期成本曲线 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本3 Topics to be Discussed lProduction with Two Outputs: Economies of Scope规模经济 lDynamic Changes in Costs: The Learning Curve长期成本曲线 200

2、5 Pearson Education, Inc.TopicstobeDiscussed衡量成本4 5.1衡量成本衡量成本 lFor a firm to minimize costs, we must clarify what is meant by costs and how to measure them mIt is clear that if a firm has to rent equipment or buildings, the rent they pay is a cost mWhat if a firm owns its own equipment or building?

3、lHow are costs calculated here? 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本5 Measuring Cost: Which Costs Matter? lAccounting Cost会计成本会计成本 m实际发生的费用和固定资产的折旧实际发生的费用和固定资产的折旧 lEconomic Cost经济成本经济成本 m企业在生产中所使用的资源的成本企业在生产中所使用的资源的成本 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本6 Measuring Cost

4、: Which Costs Matter? lOpportunity cost机会成本机会成本 m企业未将资源用于其他可供选择的最佳用途而 放弃的机会相联系的成本 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本7 Measuring Cost: Which Costs Matter? l Although opportunity costs are hidden and should be taken into account, sunk costs should not l Sunk Cost沉没成本沉没成本 m已经发生但无法收回的支出

5、已经发生但无法收回的支出 m在制定未来经济决策时应当忽略它在制定未来经济决策时应当忽略它。 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本8 Sunk Cost lFirm buys a piece of equipment that cannot be converted to another use专用 设备 lExpenditure on the equipment is a sunk cost mHas no alternative use so cost cannot be recovered opportunity cost

6、is zero mDecision to buy the equipment might have been good or bad, but now does not matter 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本9 Prospective Sunk Cost lAn Example mFirm is considering moving its headquarters mA firm paid $500,000 for an option to buy a building mThe cost of the build

7、ing is $5 million for a total of $5.5 million mThe firm finds another building for $5.25 million mWhich building should the firm buy? 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本10 Prospective Sunk Cost lExample (cont.) lThe first building should be purchased lThe $500,000 is a sunk cost and

8、should not be considered in the decision to buy lWhat should be considered is mSpending an additional $5,250,000 or mSpending an additional $5,000,000 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本11 Measuring Cost: Which Costs Matter? l总成本包括总成本包括: lFixed Cost固定成本固定成本 mDoes not vary with the le

9、vel of output lVariable Cost 可变成本可变成本 mCost that varies as output varies VC FC TC 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本12 Fixed and Variable Costs l什么成本是固定的，什么是可变的，和时什么成本是固定的，什么是可变的，和时 间长短有关间长短有关 l在短期内大多数成本固定在短期内大多数成本固定 l长期内大多数成本可变长期内大多数成本可变 2005 Pearson Education, Inc.TopicstobeDiscus

10、sed衡量成本13 固定成本与沉没成本固定成本与沉没成本 l 他们经常被混淆他们经常被混淆 l Fixed Cost m在企业经营中必须支付的成本，与产出在企业经营中必须支付的成本，与产出 水平无关水平无关 m影响企业决策影响企业决策 l Sunk Cost m已经发生无法收回的成本。不影响决策已经发生无法收回的成本。不影响决策 m将沉淀成本按摊销方式处理。不区分沉将沉淀成本按摊销方式处理。不区分沉 淀成本和固定成本淀成本和固定成本 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本14 边际成本边际成本 lMarginal Cost (MC

11、): mThe cost of expanding output by one unit mFixed costs have no impact on marginal cost, so it can be written as: q TC q VC MC 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本15 平均成本平均成本 lAverage Total Cost (ATC) mCost per unit of output mAlso equals average fixed cost (AFC) plus average variab

12、le cost (AVC) q TVC q TFC q TC ATC AVCAFC q TC ATC 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本16 7.2短期成本短期成本 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本17 短期成本的决定因素短期成本的决定因素 An xample l考察生产与成本的关系 l假设工资固定 lVC= wL q Lw q VC MC 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本18 Deter

13、minants of Short Run Costs An Example l因为 L MP L Q L L1 L for a 1 unit Q QMP l获得额外一单位产出所需要的额外的劳动 数量为 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本19 Determinants of Short Run Costs An Example l所以所以 L MP MC w l较低的劳动边际产量较低的劳动边际产量(MPL)味着较高味着较高 的边际成本的边际成本 (MC)。每当劳动的边际产。每当劳动的边际产 量降低时，边际成本上升量降低时，边际成

14、本上升 短期内，边际成本等于变化的投入短期内，边际成本等于变化的投入 要素的价格除以其边际产量要素的价格除以其边际产量 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本20 边际报酬递减和边际成本边际报酬递减和边际成本 l边际报酬递减边际产量下降边际 成本上升 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本21 成本曲线成本曲线 Output Cost ($ per year) 100 200 300 400 012345678910111213 VC Variable cost in

15、creases with production and the rate varies with increasing and decreasing returns. TC Total cost is the vertical sum of FC and VC. FC 50 Fixed cost does not vary with output 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本22 Cost Curves 0 20 40 60 80 100 120 024681012 Output (units/yr) Cost ($/u

16、nit) MC ATC AVC AFC 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本23 Cost Curves lWhen MC is below AVC, AVC is falling lWhen MC is above AVC, AVC is rising lWhen MC is below ATC, ATC is falling lWhen MC is above ATC, ATC is rising lTherefore, MC crosses AVC and ATC at the minimums mThe Average

17、Marginal relationship 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本24 Cost Curves for a Firm l The line drawn from the origin to the variable cost curve: mIts slope equals AVC mThe slope of a point on VC or TC equals MC mTherefore, MC = AVC at 7 units of output (point A) 123456789101112 13 Out

18、put P 100 200 300 400 FC VC TC A 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本25 7.3长期成本长期成本 l长期内厂商能改变所有投入要素，因长期内厂商能改变所有投入要素，因 而改变规模而改变规模 l为了实现成本最小化，厂商需要选择为了实现成本最小化，厂商需要选择 合适的投入要素组合合适的投入要素组合 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本26 Cost in the Long Run l租入资本=自有资本 lAssume Delta is

19、considering purchasing an airplane for $150 million mPlane lasts for 30 years m$5 million per year economic depreciation for the plane 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本27 Cost in the Long Run l如果场上没有购买飞机则可以将资本如果场上没有购买飞机则可以将资本 存银行获得利息收入存银行获得利息收入 $150 million l这是机会成本这是机会成本 l使用者成本使用者成

20、本=机会成本机会成本+经济折旧经济折旧= 利率利率*资产价值资产价值+经济折旧经济折旧 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本28 Cost in the Long Run lUser Cost of Capital = Economic Depreciation + (Interest Rate)*(Value of Capital) l= $5 mil + (.10)($150 mil depreciation) mYear 1 = $5 million + (.10)($150 million) = $20 million

21、mYear 10 = $5 million +(.10)($100 million) = $15 million 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本29 Cost in the Long Run l每单位资本的使用者成本：每单位资本的使用者成本： lr=折旧率折旧率+利率利率 lIn our example, depreciation rate was 3.33% and interest was 10%, so mr = 3.33% + 10% = 13.33% 2005 Pearson Education, Inc.Top

22、icstobeDiscussed衡量成本30 成本最小化的投入选择成本最小化的投入选择 l 假设：两个可变投入假设：两个可变投入: Labor (L) and capital (K) m劳动的价格：工资劳动的价格：工资 (w) m资本的价格：资本的价格：r = 折旧率折旧率 +利率（使利率（使 用者成本）用者成本） lOr 资本价格：资本价格：=租金率租金率r 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本31 Cost in the Long Run l等成本线等成本线 C = wL + rK 2005 Pearson Educatio

23、n, Inc.TopicstobeDiscussed衡量成本32 Cost in the Long Run lRewriting C as an equation for a straight line: mK = C/r - (w/r)L m等成本线的斜率等成本线的斜率=-(w/r) r w L K 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本33 给定产量的成本最小化给定产量的成本最小化 Labor per year Capital per year Isocost C2 shows quantity Q1 can be produ

24、ced with combination K2,L2 or K3,L3. However, both of these are higher cost combinations than K1,L1. Q1 Q1 is an isoquant for output Q1. There are three isocost lines, of which 2 are possible choices in which to produce Q1. C0C1 C2 A K1 L1 K3 L3 K2 L2 2005 Pearson Education, Inc.TopicstobeDiscussed衡

25、量成本34 Input Substitution When an Input Price Change：劳动价格上：劳动价格上 升升 C2 The new combination of K and L is used to produce Q1. Combination B is used in place of combination A. K2 L2 B C1 K1 L1 A Q1 If the price of labor rises, the isocost curve becomes steeper due to the change in the slope -(w/L). Lab

26、or per year Capital per year 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本35 Cost in the Long Run l成本最小化的条件成本最小化的条件 K L MP MP - MRTS L K r w L K lineisocost of Slope costminimizesfirmwhen r w MP MP K L 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本36 Cost in the Long Run lThe minimum cost

27、 combination can then be written as: rw KL MPMP 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本37 扩张路径扩张路径 Expansion Path The expansion path illustrates the least-cost combinations of labor and capital that can be used to produce each level of output in the long-run. Capital per year 25 50 75 10

28、0 150 50 Labor per year 100150300200 A $200 0 200 Units B $3000 300 Units C 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本38 Expansion Path and Long Run Costs l扩张路径描述了长期生产中每一给定产量 是能够使得成本最低的劳动和资本组合。 从中可以得到长期总成本曲线。 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本39 A Firms Long Run Total Cost

29、Curve Long Run Total Cost Output, Units/yr 100300200 Cost/ Year 1000 2000 3000 D E F 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本40 7.4长期和短期成本曲线长期和短期成本曲线 l在短期内，有部分固定投入在短期内，有部分固定投入 l厂商在长期内所有投入要素可变厂商在长期内所有投入要素可变 m在长期内，企业能够以比短期生产在长期内，企业能够以比短期生产 更低的平均成本进行生产更低的平均成本进行生产 2005 Pearson Education, Inc.

30、TopicstobeDiscussed衡量成本41 Capital is fixed at K1. To produce q1, min cost at K1,L1. If increase output to Q2, min cost is K1 and L3 in short run. The Inflexibility of Short Run Production Long-Run Expansion Path Labor per year Capital per year L2 Q2 K2 D C F E Q1 A B L1 K1 L3 P Short-Run Expansion P

31、ath In LR, can change capital and min costs falls to K2 and L2. 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本42 Long Run Versus Short Run Cost Curves l LAC m决定长期平均成本决定长期平均成本 L AC和边和边 际成本际成本 MC 形状的因素是规模形状的因素是规模 报酬递减规律。报酬递减规律。 1. 规模报酬不变规模报酬不变长期平均成本曲长期平均成本曲 线和边际成本曲线水平，是常数。线和边际成本曲线水平，是常数。 2005 Pea

32、rson Education, Inc.TopicstobeDiscussed衡量成本43 Long Run Versus Short Run Cost Curves l 规模报酬递增规模报酬递增长期平均和边长期平均和边 际成本曲线下右下方倾斜际成本曲线下右下方倾斜 l 规模报酬递减规模报酬递减长期成曲线向长期成曲线向 右上倾斜、右上倾斜、 l 长期成本曲线也是长期成本曲线也是U型的。型的。 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本44 Long Run Versus Short Run Cost Curves l长期边际成本石油长

33、期平均成本决定的: mIf LMC LAC, LAC will rise mTherefore, LMC = LAC at the minimum of LAC l当 LAC不变时， LAC and LMC 相等 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本45 Long Run Average and Marginal Cost Output Cost ($ per unit of output LAC LMC A 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本46 规模经济和规

34、模不经济规模经济和规模不经济 l规模经济 mIncrease in output is greater than the increase in inputs l规模不经济 mIncrease in output is less than the increase in inputs lU-shaped LAC shows economies of scale for relatively low output levels and diseconomies of scale for higher levels 2005 Pearson Education, Inc.TopicstobeDis

35、cussed衡量成本47 Long Run Costs l规模经济以成本-产出弹性衡量 EC AC MC QQ CC EC EC1，规模不经济，规模不经济 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本48 Long Run Costs l EC is equal to 1, MC = AC mCosts increase proportionately with output mNeither economies nor diseconomies of scale l EC 1 when MC 1 when MC AC mDisecon

36、omies of scale mBoth MC and AC are rising 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本49 短期成本和长期成本的关系短期成本和长期成本的关系 l长期成本曲线是短期成本曲线的包络线 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本50 Long Run Cost with Constant Returns to Scale lThe optimal plant size will depend on the anticipated output

37、 mIf expect to produce q0, then should build smallest plant: AC = $8 mIf produce more, like q1, AC rises mIf expect to produce q2, middle plant is least cost mIf expect to produce q3, largest plant is best 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本51 Long Run Cost with Economies and Disecon

38、omies of Scale 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本52 l长期成本曲线是短期成本曲线的包络线 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本53 7.5范围经济范围经济 l 同时生产两种产品会存在成本上的优势。 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本54 lproduct transformation curves产品转产品转 换曲线换曲线 l描绘了能以固定数量的投入生产的两种产描绘了能以固定数

39、量的投入生产的两种产 出的不同组合。出的不同组合。 l产品转换曲线向外弯曲，是因为存在生产产品转换曲线向外弯曲，是因为存在生产 的范围经济的范围经济 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本55 Product Transformation Curve Number of cars Number of tractors O1 illustrates a low level of output. O2 illustrates a higher level of output with two times as much labor a

40、nd capital. Each curve shows combinations of output with a given combination of L & K. O2 O1 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本56 Production with Two Outputs Economies of Scope lThe degree of economies of scope (SC) 范围经济程度： mC(q1) is the cost of producing q1 mC(q2) is the cost of pr

41、oducing q2 mC(q1,q2) is the joint cost of producing both products )qC(q )qC(q)C(q)C(q SC , , 21 2121 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本57 Production with Two Outputs Economies of Scope lWith economies of scope, the joint cost is less than the sum of the individual costs lInterpretat

42、ion: mIf SC 0 Economies of scope mIf SC 0 and N increases, mL approaches A, and A represents minimum labor input/unit of output after all learning has taken place lThe larger , mThe more important the learning effect 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本66 The Learning Curve Cumulative

43、 number of machine lots produced Hours of labor per machine lot 10203040500 2 4 6 8 10 The chart shows a sharp drop in lots to a cumulative amount of 20, then small savings at higher levels. Doubling cumulative output causes a 20% reduction in the difference between the input required and minimum at

44、tainable input requirement. 31. 0 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本67 Dynamic Changes in Costs The Learning Curve l Observations lNew firms may experience a learning curve, not economies of scale lShould increase production of many lots regardless of individual lot size lOlder firm

45、s have relatively small gains from learning 1.Should produce their machines in very large lots to take advantage of lower costs associated with size 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本68 Economies of Scale Versus Learning Output Cost ($ per unit of output) AC1 B Economies of Scale A

46、AC2 Learning C 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本69 Predicting Labor Requirements of Producing a Given Output 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本70 Dynamic Changes in Costs The Learning Curve l From the table, the learning curve implies: lThe labor requirement falls

47、per unit lCosts will be high at first and then will fall with learning 1.After 8 years, the labor requirement will be 0.51 and per unit cost will be half what it was in the first year of production 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本71 The Learning Curve in Practice l Scenario mA new

48、 firm enters the chemical processing industry l Do they: mProduce a low level of output and sell at a high price? 1.Produce a high level of output and sell at a low price? 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本72 The Learning Curve in Practice lThe Empirical Findings mStudy of 37 chemic

49、al products lAverage cost fell 5.5% per year lFor each doubling of plant size, average production costs fall by 11% lFor each doubling of cumulative output, the average cost of production falls by 27% lWhich is more important, the economies of scale or learning effects? 2005 Pearson Education, Inc.T

50、opicstobeDiscussed衡量成本73 The Learning Curve in Practice lOther Empirical Findings mIn the semiconductor industry, a study of seven generations of DRAM semiconductors from 1974-1992 found learning rates averaged 20% mIn the aircraft industry, the learning rates are as high as 40% 2005 Pearson Educati

51、on, Inc.TopicstobeDiscussed衡量成本74 The Learning Curve in Practice l Applying Learning Curves lTo determine if it is profitable to enter an industry 1.To determine when profits will occur based on plant size and cumulative output 2005 Pearson Education, Inc.TopicstobeDiscussed衡量成本75 Estimating and Pre

52、dicting Cost lEstimates of future costs can be obtained from a cost function, which relates the cost of production to the level of output and other variables that the firm can control lSuppose we wanted to derive the total cost curve for automobile production 2005 Pearson Education, Inc.TopicstobeDi