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1 前言我們每天所享用的商品與服務都是由廠商所生產, 如通用汽車公司製造小轎車, 奇異電器生產電燈泡, 家樂氏專門做早餐吃的玉米片大公司裡, 不但雇用數以千計的員工, 同時也擁有許多的股東分享利潤我們曾以廠商的供給曲線來解釋其生產決策根據供給法則, 當商品的價格越高時, 廠商願意生產且供給的數量必然越多, 所以供給曲線的斜率為正在 ch13~ch17 中, 我們將更深入探討生產者 ( 廠商 ) 的行為這個主題會讓你瞭解那一些決策會影響市場的供給曲線也會介紹生產組織 - 即研究廠商對價格數量的決策如何取決於其所面對的市場狀況例如 : 你所住的地方可能有好幾個便利商店, 卻只有一家有線電視這令我們想到一關鍵問題 : 由於廠商的家數不同, 其在市場中的訂價策略與市場效率是否也有所不同? 產業組織學就是針對此項問題在做研究 1

2 第十三章生產成本本章欲探討底下問題 : 成本收益利潤何謂生產函數? 邊際產出? 兩者之關係為何? 何謂變動成本? 與其他成本及產出的關係? 長短期成本的差異? 何謂規模經濟? 2

3 總收益總成本利潤我們假設廠商的目標是利潤 = 總收益總成本 Profit = Total revenue Total cost 廠商出售商品與服務之所得金額廠商為了購買生產要素所支付的成本 3

4 成本 - 外顯成本與隱藏成本機會成本 : 為了要得到某一特定物品所需放棄最佳其他選擇所能帶來的利益外顯成本 Explicit costs: 能以客觀標準認定的會計支出 ex. 支付給員工的薪資支出隱藏成本 Implicit costs : 無法以客觀記帳標準認定的一切機會成本 ex. 時間的機會成本業主的自有資金 Remember one of the Ten Principles: The cost of something is what you give up to get it. This is true whether the costs are implicit or explicit. Both matter for firms decisions. 4

5 Explicit vs. Implicit Costs: An Example You need $100,000 to start your business. The interest rate is 5%. Case 1: borrow $100,000 explicit cost = $5000 interest on loan Case 2: use $40,000 of your savings, borrow the other $60,000 explicit cost = $3000 (5%) interest on the loan implicit cost = $2000 (5%) foregone interest you could have earned on your $40,000. In both cases, total (exp + imp) costs are $

6 成本 - 經濟學者與會計學者的觀點經濟學者有興趣的是經濟利潤 (economic profit) - 廠商的總收益減去總成本, 而總成本包括外顯成本與隱藏成本 Economic profit = total revenue - total costs (including explicit and implicit costs) = total revenue - explicit costs - implicit costs 會計人員注重的是會計利潤 (accounting profit) - 廠商的總收益減去其外顯成本的淨額 Accounting profit = total revenue - total explicit costs 從經濟學家的角度來看, 企業要獲利, 總收益必須能支應所有的機會成本, 不論其是外顯的或是隱藏的 6

7 成本 - 經濟學者與會計學者的觀點 Economic profit = total revenue - total costs (including explicit and implicit costs) = total revenue - explicit costs - implicit costs = Accounting profit - implicit costs 經濟利潤 < 會計利潤經濟利潤是項重要的觀念因為它是廠商願意提供商品與服務的動機有賺得經濟利潤的廠商會持續經營, 其收入在扣除了所有機會成本後, 仍有剩餘可以回饋業主當廠商處於經濟虧損時 ( 即賺取的經濟利潤為負值 ), 業主無法彌補所有的生產成本, 除非情況有所改變, 他終將關門並退出產業 7

8 圖 1 經濟學家與會計人員 8

9 A C T I V E L E A R N I N G 2: Economic profit vs. accounting profit The equilibrium rent on office space has just increased by $500/month. Compare the effects on accounting profit and economic profit if a. you rent your office space b. you own your office space 9

10 生產與成本 - 生產函數生產函數 ( production function) 用以描述廠商在各種生產要素投入數量與其所對應之最大商品或服務產出數量間技術關係的函數 Example 1: Farmer Jack grows wheat. He has 5 acres of land. He can hire as many workers as he wants. 10

11 生產與成本 - 生產函數 uantity of output Example 1 : Farmer Jack s Production Function L (no. of workers) (bushels of wheat) 3,000 2, , , , No. of workers 11

12 生產與成本 - 邊際產量邊際產量 (marginal product) 每增加一單位投入要素所能增加的產量例如 : 如果農夫 Jack 多雇用一個員工, 其產出額外增加多少 Notation: (delta) = change in Examples: = change in output, L = change in labor 勞動邊際產量 Marginal product of labor 12

13 生產與成本 - 邊際產量 EXAMPLE 1: Total & Marginal Product L (no. of (bushels workers) of wheat) MPL L = 1 L = 1 L = 1 L = 1 L = = 1000 = 800 = 600 = 400 =

14 生產與成本 - 邊際產量 EXAMPLE 1: MPL = Slope of Prod Function L (no. of workers) (bushels of wheat) MPL MPL equals the slope of the production function. 生產函數的斜率可用以衡量每一單位勞動 ( 即員工 ) 的邊際產量 Notice that MPL diminishes as L increases. This explains why the production function gets flatter as L increases. 隨著員工人數的增加, 邊際產量下降, 生產函數曲線的走勢就趨於平緩 14

15 生產與成本 - 邊際產量 uantity of output EXAMPLE 1: MPL = Slope of Prod Function L (no. of (bushels workers) of wheat) MPL 3,000 2, ,000 1,500 1, No. of workers 15

16 生產與成本 -Why MPL Is Important Recall one of the Ten Principles: Rational people think at the margin. 當農夫 Jack 額外多雇用一名員工時 : 成本增加 - 支付工資給該名員工產出增加 - 因為 MPL 比較兩者, 可以幫助 Jack 決定是否額外多雇用一名員工生產與成本 -Why MPL Diminishes 邊際產量遞減 ( Diminishing marginal product )- 例如 : 廠商雇用的人越多, 對每一個新增的員工來說, 因為工廠的設備不夠雇用的人多, 每位新的員工所能增加的邊際產量會相對的減少 16

17 成本如何衡量 - 由生產函數到總成本曲線例如 : 農夫 Jack 的成本必須支付每個月的土地租金 $1000 以及在農場工作之員工的月薪每人 $2000. L (no. of workers) (bushels of wheat) cost of land cost of labor Total Cost 0 0 $1,000 $0 $1, $1,000 $2,000 $3, $1,000 $4,000 $5, $1,000 $6,000 $7, $1,000 $8,000 $9, $1,000 $10,000 $11,000 17

18 成本如何衡量 - 由生產函數到總成本曲線總成本曲線 (Total Cost Curve)- 描繪生產數量與總成本之間兩者的關係 (bushels of wheat) Total Cost $12,000 $10,000 0 $1, $3, $5, $7,000 Total cost $8,000 $6,000 $4,000 $2, $9, $11,000 $ uantity of wheat 18

19 (bushels of wheat) 成本如何衡量 - 邊際成本 Marginal Cost (MC) - 每增加一單位產量, 總成本增加的金額 Total Cost MC = TC Marginal Cost (MC) 0 $1,000 = 1000 TC = $ $3,000 = 800 TC = $ $5,000 = 600 TC = $ $7,000 = 400 TC = $ $9,000 = 200 TC = $ $11,000 $2.00 $2.50 $3.33 $5.00 $

20 成本如何衡量 - 邊際成本邊際成本會隨著產量的增加而上升 (bushels of wheat) TC $1,000 $3,000 $5,000 $7,000 $9,000 $11,000 MC $2.00 $2.50 $3.33 $5.00 $10.00 Marginal Cost ($) $12 $10 $8 $6 $4 $2 $0 0 1,000 2,000 3,000 20

21 成本如何衡量 - 固定成本與變動成本 ❶ Fixed costs (FC) 固定成本 : 不會隨著產出量變動而改變的成本 For Farmer Jack, FC = $1000 for his land ❷ Variable costs (VC) 變動成本 : 會隨著產出量變動而改變的成本 For Farmer Jack, VC = wages he pays workers Total cost (TC) = FC + VC 21

22 Costs EXAMPLE 2: Costs FC VC 0 $100 $0 TC $100 $800 $700 $600 FC VC TC $500 $400 $300 $200 $100 $

23 EXAMPLE 2: Marginal Cost( 邊際成本 ) TC $ MC $ Recall, Marginal Cost (MC) is $175 the change in total cost from producing one more unit: $125 TC MC = $100 Usually, MC rises as rises, due $75 to diminishing marginal product. Costs $200 $150 $50 Sometimes (as here), MC falls $25 before rising. $0 (In other examples, MC may be constant.)

24 EXAMPLE 2: Average Fixed Cost ( 平均固定成本 ) FC $ AFC n.a. $ Costs Average $200 fixed cost (AFC) is $175 fixed cost divided by the quantity of output: $150 AFC = FC/ $125 $100 Notice $75 that AFC falls as rises: The firm is spreading its fixed $50 costs over a larger and larger $25 number of units. $

25 EXAMPLE 2: Average Variable Cost ( 平均變動成本 ) VC $ AVC n.a. $ Costs Average $200 variable cost (AVC) is $175 variable cost divided by the quantity of output: $150 AVC = VC/ $125 $100 As $75 rises, AVC may fall initially. In most cases, AVC will $50 eventually rise as output rises. $25 $

26 EXAMPLE 2: Average Total Cost ( 平均總成本 ) 0 1 TC $ ATC n.a. $170 AFC n.a. $100 AVC n.a. $70 Average total cost (ATC) equals total cost divided by the quantity of output: Also,

27 Costs EXAMPLE 2: Average Total Cost ( 平均總成本 ) TC $ ATC n.a. $ $200 Usually, as in this example, $175 the ATC curve is U-shaped. $150 $125 $100 $75 $50 $ $

28 Costs EXAMPLE 2: The Various Cost Curves Together $200 $175 ATC AVC AFC MC $150 $125 $100 $75 $50 $25 $

29 成本如何衡量 - 固定成本與變動成本總成本總固定成本 (TFC)=FC1+FC2+ 總變動成本 (TVC)=VC1+VC2+ 總成本 (TC) =TFC + TVC 平均總成本因為總成本為固定與變動成本之和, 平均總成本可解釋為平均固定成本與平均變動成本之和平均總成本 = 總成本除以總產量 =TC/ 平均成本平均固定成本 (AFC)=TFC/ 平均變動成本 (AVC)=TVC/ 平均總成本 (ATC)= AFC + AVC 邊際成本 MC = TC / = 總成本的變動 / 產量的變動 30

A C T I V E L E A R N I N G 3: Costs Fill in the blank spaces of this table. VC TC AFC AVC ATC MC 0 1 10 $50 n.a. n.a. $10 n.

30 A C T I V E L E A R N I N G 3: Costs Fill in the blank spaces of this table. VC TC AFC AVC ATC MC $50 n.a. n.a. $10 n.a. $60.00 $

31 成本如何衡量 - 各種成本曲線的形狀 Costs As rises: Initially, falling AFC pulls ATC down. Eventually, rising AVC pulls ATC up. $200 $175 $150 $125 $100 $75 $50 $25 $

32 Costs When MC < ATC, ATC is falling. When MC > ATC, ATC is rising. The MC curve crosses the ATC curve at the ATC curve s minimum. 成本如何衡量 - 各種成本曲線的形狀 $200 $175 $150 $125 $100 $75 $50 $25 ATC MC $

34 短期 Short run: 短期成本與長期成本對許多廠商而言, 固定成本與變動成本的區別, 要看其所考慮的期間長短而定一些成本是固定的 (e.g., factories, land). The costs of these inputs are FC. 長期 Long run: 所有投入要素為可變動的, 一些固定的成本會轉換為變動的成本 (e.g., firms can build more factories, or sell existing ones) 因為許多在短期內固定的成本, 到了長期卻會改變, 廠商的長期成本曲線會不同於其短期成本曲線 35

35 短期成本與長期成本 EXAMPLE 3: LRATC with 3 factory Sizes 具有 3 種工廠規模的長期平均成本 Firm can choose from 3 factory sizes: S, M, L. 廠商可以由大中小三種工廠規模做選擇 Each size has its own SRATC curve. 每一種規模的工廠, 有其各自的短期平均成本 The firm can change to a different factory size in the long run, but not in the short run. 長期下, 廠商可以變換不同的工廠規模短期則不能變換 Avg Total Cost 36

36 EXAMPLE 3: LRATC with 3 factory Sizes To produce less than A, firm will choose size S in the long run. 生產少於 A, 廠商在長期會選擇小規模的工廠 To produce between A and B, firm will choose size M in the long run. 短期成本與長期成本 Avg Total Cost ATC S ATC M ATC L 生產介於 A 及 B 之間, 廠商在長期會選擇小中規模的工廠 To produce more than B, firm will choose size L in the long run. 生產多於 B, 廠商在長期會選擇大規模的工廠 A B 37

37 短期成本與長期成本 A Typical LRATC Curve In the real world, factories come in many sizes, each with its own SRATC curve. ATC So a typical LRATC curve looks like this: 38

38 規模經濟與規模不經濟 Economies of scale: 規模經濟隨著產量的增加, 長期平均總成本下降的特性 Constant returns to scale: 固定規模報酬長期平均總成本不會隨著產量增加而改變的特性 ATC LRATC Diseconomies of scale: 規模不經濟產量的增加, 長期平均總成本也隨之上升的特性 39

39 結論廠商的目標是追求最大利潤, 利潤是指總收益與總成本的差額在我們分析廠商行為時, 應考慮所有的機會成本經濟利潤 = 會計利潤 - 隱藏成本廠商的成本可反映出它的生產過程典型廠商生產函數曲線會隨著投入要素的增加漸趨平緩, 展現了邊際產量遞減律廠商的總成本可分為 : 固定成本與變動成本固定成本不會隨著產量的增減而改變 ; 變動成本則會隨著產量的改變而改變平均總成本是總成本除以總產量邊際成本則為每增加一單位產出, 總成本的變動額邊際成本曲線會隨著產量的增加而上升平均總成本曲線則會隨著產量的增加先下降再上升 U 字形的平均總成本曲線邊際成本曲線會相交於平均總成本曲線的最低點廠商一廠商的成本型態, 往往視我們所考慮的期間長短而定到了長期卻會改變, 廠商的長期成本曲線會不同於其短期成本曲線 40

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第十七章本章欲探討底下問題 : 獨佔性競爭何謂獨佔性競爭? 其與完全競爭及獨佔的關係為何? 獨佔性競爭的均衡獨佔性競爭與社會福利廣告獨佔性競爭 Monopolistic competition: 一種出售類似產品廠商數目眾多的市場結構, 其中