1. Costs of Production KW Chapter 8

2. Costs: Explicit vs. Implicit Explicit Costs of Production: Direct payments for resources not owned by a firm (raw materials, wages, energy payments, interest payments). Opportunity Cost: (The best alternative to any action). Implicit Costs: Opportunity Costs of assets owned by firms –Ex. Owner of barbershop could earn $100 per hour working as a barber. Implicit cost of the owners time is $100 per hour. –Opportunity cost of equity capital is return that could have been earned elsewhere.

3. Short-Run vs. Long Run Firms typically have several types of inputs that they can adjust to adjust production. Long-run - When firms are able to adjust all of their inputs including physical plant. Short-run – When firms are able to adjust only some of their inputs (usually energy, labor, and raw material costs).

4. Production in the Short-Run Given a set of fixed inputs (like plant and capital equipment), a firm can vary other inputs (typically labor) and to vary production. Typically, as you add workers, you get more output. But, diminishing returns sets in, and the addition of extra workers will generate less and less extra production.

5. Labor Productivity Function Output Labor

6. Short Run Production Function ΔLabor ΔOutput ΔLabor ΔOutput

7. Marginal Product Function Labor

8. Increasing Marginal Product at Low Production Levels Up to a point each additional worker adds synergy and adding more workers leads to more and more extra pay-off. When a production plant is operating below capacity, adding more workers can generate more output at a relatively constant rate.

9. Fixed Costs vs. Variable Costs In short-run, we distinguish between the costs that are adjustable as production is adjusted (variable costs) and costs that are unchanged regardless of production (fixed costs). –Variable costs (Wages of production workers, supply and raw materials costs, short-term finance costs) –Fixed costs (Depreciation costs, Financial costs, wages of non-production workers).

10. Cost Shares Various 4 Digit Industry (USA, 1991-1996) NBER Productivity Database

11. Types of Costs Total Fixed Costs – Invariant to the number of goods produced (in the short- run) Total Variable Costs- Increasing in the number of goods produced. Total Costs: Fixed Costs + Variable Costs

12. Bakery: Wages $10 per Worker, $5 Wheat per Loaf

13. Total Variable Costs are increasing at an accelerating rate. Reason: Diminishing returns to variable inputs.

14. Costs: Average vs. Marginal Total Costs are the sum of all relevant costs for a firm. Average Costs: Costs per unit of output. Marginal Cost: Extra Cost per Extra Unit of Output.

15. Average and Marginal Costs Average Fixed Costs decreases as production increases AVC, ATC, MC all increase as diminishing returns kick in MC equals AVC and ATC when each of the latter are at their minimum level.

16. Cost Schedules

17. Costs in the Long Run In the short-run, the size of a firms physical plant is a fixed factor. Over-time, the plant size can adjust. In the bakery example, extra ovens can be added.

18. Minimizing Costs in the Long Run Consider average total cost schedules at different numbers of ovens. Each oven will have a production level that generates the minimum average total cost. To minimize average costs in the long-run, choose the number of ovens which will have the lowest, minimum average total cost.

19. Average Total Cost Schedules at Different Scales of Production

20. Minimum of the different cost Schedules

21. Connect the Dots Long Run Average Total Costs

22. If we adjust capital scale continuously, the collection of minimum points is the Long Run Average Total cost cuve LR ATC Short-run ATC

23. Economies of Scale When firms are able to adjust all of their inputs, they can choose a size that will minimize costs. If a firm is able to achieve some economies of scale, increasing size will reduce the average total cost. Sources of Economies of Scale –Production requires major expenditure on items needed to produce even zero products Ex. Software, pharmaceuticals –Production requires many specific steps which can be most efficiently done through specialization Ex. Airplanes, automobiles

24. Long Run ATC increasing returns to scale. Output Costs LR ATC Economies of Scale

25. Returns to Scale Scale Economies is not always likely to characterize production. If each production unit can act autonomously with identical costs then we may experience constant returns to scale. Firms at some point experience diseconomies of scale or increasing long run average total costs. Sources of diseconomies of scale –Limits of managerial invention. –Limits of some other fixed resource.

26. Long Run ATC decreasing returns to scale. Output Costs LR ATC Constant Returns Scale Diseconomies

27. Overall Cost Function LR ATC Minimum Efficient Scale

28. MES and Market Structure If MES is relatively large in comparison with the market demand: $ Q D LRAC The market is most efficiently served by a single firm---natural monopoly!

29. MES and Market Structure If MES is relatively small in comparison with market demand: $ Q Many “small” firms in the market.

30. Typical Scale varies across sectors in USA 2002 Census of Manufactures

31. Learning Outcomes Students should be able to Define and calculate various types of economic costs. –Explicit, implicit, fixed, variable, total, average, marginal, economic, accounting. Describe the shape of various relevant cost curves – Average Total (in LR and SR), Average Fixed, Marginal Costs Describe the relationship between production, productivity (marginal and average) and the law of diminishing returns.