THE ECONOMY AT FULL EMPLOYMENT: THE CLASSICAL MODEL

1. 24 THE ECONOMY AT FULL EMPLOYMENT: THE CLASSICAL MODEL CHAPTER 充分就業下的經濟:古典模型

2. Objectives • After studying this chapter, you will able to • Describe the relationship between the quantity of labor employed and real GDP • Explain what determines the demand for labor and the supply of labor and how labor market equilibrium determines employment, the real wage rate, and potential GDP

3. Objectives • After studying this chapter, you will able to • Explain how business investment decisions and household saving decisions are made • Explain how investment and saving interact to determine the real interest rate • Use the classical model to explain the forces that change potential GDP

4. Our Economy’s Compass • Our economy follows a path like that of an explorer probing new terrain. • Sometimes the explorer strays of course. • But the explorer has a compass that helps keep getting back on the main track. • Our economy wanders around its main course—its full employment trend—but like the explorer, has a compass that keeps bringing it back. • The classical model is the compass and you’ll learn about it in this chapter.

5. The Classical Model: A Preview • Economists have made progress in understanding how the economy works by dividing the variables that describe macroeconomic performance into two lists: • Real variables實質變數 • Nominal variables名目變數 • Real variables like real GDP, employment, and the real wage rate describe what is happening to living standards • Nominal variables like the price level and nominal wage rate tell us how dollar values and the value of money are changing.

6. The Classical Model: A Preview • The two lists of variables form the basis of a huge discovery called the classical dichotomy古典二分法, which states: • At full employment, the forces that determine real variables are independent of those that determine nominal variables. • For example, we can explain why real GDP in the United States is 20 times that of Nigeria by looking only at real variables. We don’t need to look at the price levels in the two countries.

7. The Classical Model: A Preview • The classical model is a model of the economy that determines the real variables—real GDP, employment and unemployment, the real wage rate, consumption, saving, investment, and the real interest rate—at full employment. • Most economists believe that the economy is rarely at full employment but that the classical model provides a benchmark against which to measure the actual state of the economy.

8. Real GDP and Employment • Production Possibilities • The production possibility frontier (PPF) is the boundary between those combinations of goods and services that can be produced and those that cannot.

9. Real GDP and Employment • Figure 24.1(a) illustrates a production possibility frontier between leisure time and real GDP. • The more leisure time forgone, the greater is the quantity of labor employed and the greater is the real GDP.

10. Real GDP and Employment • The PPF showing the relationship between leisure time and real GDP is bowed-out, which indicates an increasing opportunity cost. • Opportunity cost is increasing because the most productive labor is used first and as more labor is used it is increasingly less productive.

11. Real GDP and Employment • The Production Function • The production function is the relationship between real GDP and the quantity of labor employed, other things remaining the same. • One more hour of labor employed means one less hour of leisure, therefore the production function is the mirror image of the leisure time-real GDP PPF.

12. Real GDP and Employment • Figure 24.1(b) illustrates the production function that corresponds to the PPF shown in Figure 24.1(a). • Along the production function, an increase in labor hours brings an increase in real GDP.

13. The Labor Market and Potential GDP • To understand how potential GDP is determined, we study: • The demand for labor勞動供給 • The supply of labor勞動需求 • Labor market equilibrium勞動市場均衡 • Potential GDP 潛力國內生產毛額

14. The Labor Market and Potential GDP • The Demand for Labor • The quantity of labor demanded is the labor hours hired by all firms in the economy. • The demand for labor is the relationship between the quantity of labor demanded and the real wage rate, other things remaining the same. • The real wage rate is the quantity of good and services that an hour of labor earns. • The money wage rate is the number of dollars an hour of labor earns.

15. The Labor Market and Potential GDP • To calculate the real wage rate, we divide the money wage rate by the GDP deflator and multiply by 100. • It is the real wage rate, not the money wage rate, that determines the quantity of labor demanded. • Figure 24.2 shows a demand for labor curve.

16. The Labor Market and Potential GDP • The demand for labor depends on the marginal product of labor, which is the additional real GDP produced by an additional hour of labor when all other influences on production remain the same. • The marginal product of labor is governed by the law of diminishing returns, which states that as the quantity of labor increases, but the quantity of capital and technology remain the same, the marginal product of labor decreases.

17. The Labor Market and Potential GDP • We calculate the marginal product of labor as the change in real GDP divided by the change in the quantity of labor employed.

18. The Labor Market and Potential GDP • Figure 24.3 shows the calculation of the marginal product of labor and illustrates the relationship between the marginal product curve and the production function.

19. The Labor Market and Potential GDP • A 100 billion hour increase in labor from 100 to 200 billion hours brings a $4 trillion increase in real GDP—the marginal product of labor is $40 an hour.

20. The Labor Market and Potential GDP • A 100 billion hour increase in labor from 200 to 300 billion hours brings a $3 trillion increase in real GDP—the marginal product of labor is $30 an hour. • The marginal product of labor is the slope of the production function.

21. The Labor Market and Potential GDP • Figure 24.3(b) shows the same information on the marginal product curve, MP. • At 150 (midway between 100 and 200), marginal product is $40. • At 250 (midway between 200 and 300), marginal product is $30.

22. The Labor Market and Potential GDP • The marginal product of labor curve is the demand for labor curve. • Firms hire more labor as long as the marginal product of labor exceeds the real wage rate. • With the diminishing marginal product of labor, the extra output from an extra hour of labor is exactly what the extra hour of labor costs, i.e. the real wage rate. • At this point, the profit-maximizing firm hires no more labor.

23. The Labor Market and Potential GDP • The Supply of Labor • The quantity of labor supplied is the number of labor hours that all the households in the economy plan to work at a given real wage rate. • The supply of labor is the relationship between the quantity of labor supplied and the real wage rate, all other things remaining the same.

24. The Labor Market and Potential GDP • Figure 24.4 illustrates a labor supply curve. • The higher the real wage rate, the greater is the quantity of labor supplied.

25. The Labor Market and Potential GDP • The quantity of labor supplied increases as the real wage rate increases for two reasons: • Hours per person increase每人工時增加 • Labor force participation increases勞動力之參與增加

26. The Labor Market and Potential GDP • Hours per person每人工時increase because the real wage rate is the opportunity cost of not working. • But a higher real wage rates increase income, which increases the demand for normal goods, including leisure. • An increase in the quantity of leisure demanded means a decrease in the quantity of labor supplied. • The opportunity cost effect is usually greater than the income effect, so a rise in the real wage rate brings an increase in the quantity of labor supplied.

27. The Labor Market and Potential GDP • Labor force participation勞動力之參與increases because higher real wage rates induce some people who choose not to work at lower real wage rates to enter the labor force. • The labor supply response to an increase in the real wage rate is positive but small. • A large percentage increase in the real wage rate brings a small percentage increase in the quantity of labor supplied. • The labor supply curve is relatively steep.

28. The Labor Market and Potential GDP • The labor market is in equilibrium at the real wage rate at which the quantity of labor demanded equals the quantity of labor supplied. • Labor market equilibrium is full-employment equilibrium. • The level of real GDP at full employment is potential GDP.

29. The Labor Market and Potential GDP • Figure 24.5(a) illustrates labor market equilibrium. • Labor market equilibrium occurs at a real wage rate of $35 and an employment of 200 billion labor hours.

30. The Labor Market and Potential GDP • Potential GDP • At a full employment level of 200 billion hours, potential GDP is 10 trillion dollars.

31. Unemployment at Full Employment • The unemployment rate at full employment is called the natural rate of unemployment. • Unemployment always is present for two broad reasons • Job search工作尋找 • Job rationing工作配給

32. Unemployment at Full Employment • Job Search工作尋找 • Job search is the activity of workers looking for an acceptable vacant job. • All unemployed workers search for new jobs, and while they search many are unemployed.

33. Unemployment at Full Employment • Figure 24.6 illustrates the relationship between the amount of job search unemployment and the real wage rate.

34. Unemployment at Full Employment • The amount of job search unemployment changes over time and the main sources of these changes are • Demographic change • Unemployment compensation • Structural change

35. Unemployment at Full Employment • Demographic change區域流動性問題 • As more young workers entered the labor force in the 1970s, the amount of frictional unemployment increased as they searched for jobs. • Frictional unemployment(摩擦性失業) may have fallen in the 1980s as those workers aged. • Two-earner households may increase search, because one member can afford to search longer if the other has an income.

36. Unemployment at Full Employment • Unemployment compensation失業救助 • The more generous unemployment benefit payments become, the lower the opportunity cost of unemployment, so the longer workers search for better employment rather than any job. • More workers are covered now by unemployment insurance than before, and the payments are relatively more generous.

37. Unemployment at Full Employment • Structural change結構性失業 • An increase in the pace of technological change that reallocates jobs between industries or regions increases the amount of search.

38. Unemployment at Full Employment • Job Rationing工作配給 • Job rationing occurs when employed workers are paid a wage that creates an excess supply of labor. • Job rationing can occur for two reasons • Efficiency wage效率工資 • Minimum wage最低工資

39. Unemployment at Full Employment • An efficiency wage效率工資is a real wage rate that is set above the full-employment equilibrium wage that balances the costs and benefits of this higher wage rate to maximize the firm’s profit. • The cost of a higher wage is direct. • The benefit of a higher wage is indirect: it enables a firm to attract high-productivity workers, stimulates greater work effort, lowers the quit rate, and lowers recruiting costs.

40. Unemployment at Full Employment • A minimum wage最低工資is the lowest wage rate at which a firm may legally hire labor. • If the minimum wage is set below the equilibrium wage rate, it has no effect. • If the minimum wage is set above the equilibrium wage rate, it does affect the labor market.

41. Unemployment at Full Employment • Job Rationing and Unemployment　工作配給與失業 • If the real wage rate is above the equilibrium wage, regardless of the reason, there is a surplus of labor that adds to unemployment and increases the natural unemployment rate. • Most economists agree that efficiency wages and minimum wages increase the natural unemployment rate. • David Card and Alan Krueger have challenged this view and argue that an increase in the minimum wage works like an efficiency wage, making workers more productive and less likely to quit.

42. Investment, Saving, and the Interest Rate • Investment and Capital • The capital stock is the total amount of plant, equipment, buildings, and inventories, physical capital. • Gross investment is the purchase of new capital. • Depreciation is the wearing out of the capital stock. • Net investment equals gross investment minus depreciation, and net investment is the addition to the capital stock.

43. Investment, Saving, and the Interest Rate • Investment Decisions • Business investment decisions are influenced by • The expected profit rate預期獲利率 • The real interest rate實質利率

44. Investment, Saving, and the Interest Rate • The Expected Profit Rate • The expected profit rate is relatively high during business cycle expansions and relatively low during recessions. • Advances in technology can increase the expected profit rate. • Taxes affect the expected profit rate because firms are concerned about after-tax profits.

45. Investment, Saving, and the Interest Rate • The Real Interest Rate • The real interest rate is the opportunity cost of the funds used to finance investment. • Regardless of whether a firm borrows or uses its own financial resources, it faces this opportunity cost. • Either it pays the interest or it forgoes interest on its own funds.

46. Investment, Saving, and the Interest Rate • Investment Demand • Investment demand is the relationship between the level of planned investment and the real interest rate. • Figure 24.7 illustrates an investment demand curve.

47. Investment, Saving, and the Interest Rate • The investment demand curve slopes downward. • A fall in the real interest rate increases planned investment along investment demand curve. • A rise in the real interest rate decreases planned investment along investment demand curve.

48. Investment, Saving, and the Interest Rate • Saving • Investment is financed by national saving and borrowing from the rest of the world. • Saving is current income minus current expenditure, and in part finances investment.

49. Investment, Saving, and the Interest Rate • Personal saving is personal disposable income minus consumption expenditure. • Business saving is retained profits and additions to pension funds by businesses. • Government saving is the government’s budget surplus. • Any of these components can be negative. • National saving is the sum of private saving and government saving. • Households divide their disposable income between consumption expenditure and saving.

50. Investment, Saving, and the Interest Rate • Saving is influenced by • The real interest rate實質利率 • Disposable income可支配所得 • Wealth財富 • Expected future income預期未來所得