ECON 211 Lecture Chapter Six, Spring 2015

1 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education PART The Market System Choices Made by Households and Firms II 2 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE II.1 Firm and Household Decisions Households demand in output markets and supply labor and capital in input markets. To simplify our analysis, we have not included the government and international sectors in this circular flow diagram. These topics will be discussed in detail later. 3 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE II.2 Understanding the Microeconomy and the Role of Government To understand how the economy works, it helps to build from the ground up. We start in Chapters 6–8 with an overview of household and firm decision making in simple perfectly competitive markets. In Chapters 9–11, we see how firms and households interact in output markets (product markets) and input markets (labor/land and capital) to determine prices, wages, and profits. Once we have a picture of how a simple perfectly competitive economy works, we begin to relax assumptions. Chapter 12 is a pivotal chapter that links perfectly competitive markets with a discussion of market imperfections and the role of government. In Chapters 13–19, we cover the three noncompetitive market structures (monopoly, monopolistic competition, and oligopoly), externalities, public goods, uncertainty and asymmetric information, and income distribution as well as taxation and government finance. 4 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education perfect competition An industry structure in which there are many firms, each being small relative to the industry and producing virtually identical products, and in which no firm is large enough to have any control over prices. homogeneous products Undifferentiated outputs; products that are identical to or indistinguishable from one another. perfect knowledge The assumption that households possess a knowledge of the qualities and prices of everything available in the market and that firms have all available information concerning wage rates, capital costs, and output prices. Basic assumptions pertaining to Chapters 6-12: 5 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education CHAPTER OUTLINE6 Household Behavior and Consumer Choice Household Choice in Output Markets The Determinants of Household Demand The Budget Constraint The Equation of the Budget Constraint The Basis of Choice: Utility Diminishing Marginal Utility Allocating Income to Maximize Utility The Utility-Maximizing Rule Diminishing Marginal Utility and Downward-Sloping Demand Income and Substitution Effects The Income Effect The Substitution Effect Household Choice in Input Markets The Labor Supply Decision The Price of Leisure Income and Substitution Effects of a Wage Change Saving and Borrowing: Present versus Future Consumption A Review: Households in Output and Input Markets Appendix: Indifference Curves 6 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education Every household must make three basic decisions: 1. How much of each product, or output, to demand 2. How much labor to supply 3. How much to spend today and how much to save for the future Household Choice in Output Markets 7 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education Several factors influence the quantity of a given good or service demanded by a single household:  The price of the product  The income available to the household  The household’s amount of accumulated wealth  The prices of other products available to the household  The household’s tastes and preferences  The household’s expectations about future income, wealth, and prices Household Choice in Output Markets The Determinants of Household Demand 8 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education Household Choice in Output Markets The Budget Constraint Preferences, Tastes, Trade-Offs, and Opportunity Cost Within the constraints imposed by limited incomes and fixed prices, households are free to choose what they will and will not buy. Whenever a household makes a choice, it is weighing the good or service that it chooses against all the other things that the same money could buy. As long as a household faces a limited budget—and all households ultimately do—the real cost of any good or service is the value of the other goods and services that could have been purchased with the same amount of money (opportunity cost). 9 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education budget constraint The limits imposed on household choices by income, wealth, and product prices. choice set or opportunity set The set of options that is defined and limited by a budget constraint. TABLE 6.1 Possible Budget Choices of a Person Earning $1,000 per Month after Taxes Option Monthly Rent Food Other Expenses Total Available? A $ 400 $250 $350 $1,000 Yes B 600 200 200 1,000 Yes C 700 150 150 1,000 Yes D 1,000 100 100 1,200 No Household Choice in Output Markets The Budget Constraint 10 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE 6.1 Budget Constraint and Opportunity Set for Ann and Tom A budget constraint separates those combinations of goods and services that are available, given limited income, from those that are not. The available combinations make up the opportunity set. real income The set of opportunities to purchase goods and services available to a household as determined by prices and money income. So while your nominal income might go up, your real income might do down if price inflation is larger than the income increase. Household Choice in Output Markets The Budget Constraint The Budget Constraint More Formally 11 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education In general, the budget constraint can be written PXX + PYY = I, where PX = the price of X, X = the quantity of X consumed, PY = the price of Y, Y = the quantity of Y consumed, and I = household income. The budget constraint can also be re-written in graphical form The Equation of the Budget Constraint Household Choice in Output Markets Y = I/PY – (PX/PY )X 12 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education Consuming one more X forces the consumer to reduce consumption of Y by Px/Py The Equation of the Budget Constraint Household Choice in Output Markets Y = I/Py – (Px/Py )X 13 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education Y X Slope is -px/py +1 -px/py Household Choice in Output Markets The Equation of the Budget Constraint 14 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE 6.2 The Effect of a Decrease in Price on Ann and Tom’s Budget Constraint When the price of a good decreases, the budget constraint swivels to the right, increasing the opportunities available and expanding choice. The Equation of the Budget Constraint Household Choice in Output Markets Budget Constraints Change When Prices Rise or Fall Y = I/Py – (↓Px/Py )X 15 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education The Equation of the Budget Constraint Household Choice in Output Markets Budget Constraints Change When Income Rise Y = ↑I’/Py – (Px/Py )X Y Y2 (=I’/Py) Y1(=I/Py) X X1 (=I/Px) X2 (=I’/Px) New higher income I’ 16 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education The Equation of the Budget Constraint Household Choice in Output Markets Budget Constraints Change With Equi-Proportionate Price Change Y Y2 (=I/0.9Py) Y1(=I/Py) X X1 (=I/Px) X2 (=I/0.9Px) A 10% price decrease for both goods: (-0.1PX +PX )X + (-0.1PY +PY )Y = I, (0.9PX )X + (0.9PY )Y = I, 0.9(PX X + PY Y) = I, PX X + PY Y = I/0.9 17 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education utility The satisfaction a product yields. marginal utility (MU) The additional satisfaction gained by the consumption or use of one more unit of a good or service. total utility The total amount of satisfaction obtained from consumption of a good or service. law of diminishing marginal utility The more of any one good consumed in a given period, the less satisfaction (utility) generated by consuming each additional (marginal) unit of the same good. The Basis of Choice: Utility Diminishing Marginal Utility 18 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education TABLE 6.2 Total Utility and Marginal Utility of Trips to the Club per Week Trips to Club Total Utility Marginal Utility 1 12 12 2 22 10 3 28 6 4 32 4 5 34 2 6 34 0  FIGURE 6.3 Graphs of Frank’s Total and Marginal Utility Marginal utility is the additional utility gained by consuming one additional unit of a commodity—in this case, trips to the club. When marginal utility is zero, total utility stops rising. The Basis of Choice: Utility Diminishing Marginal Utility 19 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE 6.4 Diminishing Marginal Utility and Downward-Sloping Demand At a price of $40, the utility gained from even the first Thai meal is not worth the price. However, a lower price of $25 lures Ann and Tom into the Thai restaurant 5 times a month. (The utility from the sixth meal is not worth $25.) If the price is $15, Ann and Tom will eat Thai meals 10 times a month— until the marginal utility of a Thai meal drops below the utility they could gain from spending $15 on other goods (opportunity cost!). At 25 meals a month, they cannot tolerate the thought of another Thai meal even if it is free. The Basis of Choice: Utility Diminishing Marginal Utility and Downward-Sloping Demand 20 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education TABLE 6.3 Allocation of Fixed Expenditure per Week Between Two Alternatives (1) Trips to Club per Week (2) Total Utility (3) Marginal Utility (MU) (4) Price (P) (5) Marginal Utility per Dollar (MU/P) 1 12 12 $3.00 4.0 2 22 10 3.00 3.3 3 28 6 3.00 2.0 4 32 4 3.00 1.3 5 34 2 3.00 0.7 6 34 0 3.00 0 (1) Basketball Games per Week (2) Total Utility (3) Marginal Utility (MU) (4) Price (P) (5) Marginal Utility per Dollar (MU/P) 1 21 21 $6.00 3.5 2 33 12 6.00 2.0 3 42 9 6.00 1.5 4 48 6 6.00 1.0 5 51 3 6.00 0.5 6 51 0 6.00 0 The Basis of Choice: Utility Allocating Income to Maximize Utility 2 good and prices 21 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education In general, utility-maximizing consumers spread out their expenditures until the following condition holds: utility-maximizing rule Equating the ratio of the marginal utility of a good to its price for all goods. What happens if the two ratios are not equal? The Basis of Choice: Utility The Utility-Maximizing Rule where MUX is the marginal utility derived from the last unit of X consumed, MUY is the marginal utility derived from the last unit of Y consumed, PX is the price per unit of X, and PY is the price per unit of Y. for all goods, - maximizing rule : utility Y Y X X P MU P MU  22 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education We base the following analysis on four assumptions: 1. We assume that this analysis is restricted to goods that yield positive marginal utility, or, more simply, that “more is better.” 2. The marginal rate of substitution is defined as MUX/MUY, or the ratio at which a household is willing to substitute X for Y. We assume a diminishing marginal rate of substitution. 3. We assume that consumers have the ability to choose among the combinations of goods and services available and the more mixed the bundle of goods the more satisfied they are (convexity of indifference curve). 4. We assume that consumer choices are consistent with a simple assumption of rationality (no crossing indifference curves) CHAPTER 6 APPENDIX Indifference Curves Assumptions 23 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE 6A.1 An Indifference Curve An indifference curve is a set of points, each representing a combination of some amount of good X and some amount of good Y, that all yield the same amount of total utility. The consumer depicted here is indifferent between bundles A and B, B and C, and A and C. Because “more is better,” our consumer is unequivocally worse off at A' than at A. CHAPTER 6 APPENDIX Indifference Curves Deriving Indifference Curves 24 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE 6A.1 An Indifference Curve CHAPTER 6 APPENDIX Indifference Curves Convexity All the bundles on the green line are different weighted averages of bundles A and B. Because of the convexity assumption, which states that consumers like to mix goods, these bundles will be on a higher indifference curve 25 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE 6A.2 A Preference Map: A Family of Indifference Curves Each consumer has a unique family of indifference curves called a preference map. Higher indifference curves represent higher levels of total utility. ) ( Y MU X MU Y X               Y X MU MU X Y The slope of an indifference curve is the ratio of the marginal utility of X to the marginal utility of Y, and it is negative. CHAPTER 6 APPENDIX Indifference Curves Properties of Indifference Curves When we divide both sides by MUY and by X, we obtain  26 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE 6A.3 Consumer Utility-Maximizing Equilibrium Consumers will choose the combination of X and Y that maximizes total utility. Graphically, the consumer will move along the budget constraint until the highest possible indifference curve is reached. At that point, the budget constraint and the indifference curve are tangent. This point of tangency occurs at X* and Y* (point B). Y X Y X P P MU MU   Y Y X X P MU P MU  CHAPTER 6 APPENDIX Indifference Curves Consumer Choice slope of indifference curve = slope of budget constraint By multiplying both sides of this equation by MUY and dividing both sides by PX, we can rewrite this utility-maximizing rule as 27 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE 6A.4 Deriving a Demand Curve from Indifference Curves and Budget Constraint Indifference curves are labeled i1, i2, and i3; budget constraints are shown by the three diagonal lines from I/PY to I/PX 1, I/PX 2 and I/PX 3. Lowering the price of X from PX 1 to PX 2 and then to PX 3 swivels the budget constraint to the right. At each price, there is a different utility-maximizing combination of X and Y. Utility is maximized at point A on i1, point B on i2, and point C on i3. Plotting the three prices against the quantities of X chosen results in a standard downward-sloping demand curve. CHAPTER 6 APPENDIX Indifference Curves Deriving a Demand Curve from Indifference Curves and Budget Constraints I 28 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education Price changes affect households in two ways. First, if we assume that households confine their choices to products that improve their well-being, then a decline in the price of any product, ceteris paribus, will make the household unequivocally better off. In other words, if a household continues to buy the same amount of every good and service after the price decrease, it will have income left over. That extra income may be spent on the product whose price has declined, hereafter called good X, or on other products. The change in consumption of X due to this improvement in well- being is called the income effect of a price change. Income and Substitution Effects The Income Effect 29 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education When the price of a product falls, that product also becomes relatively cheaper. That is, it becomes more attractive relative to potential substitutes. A fall in the price of product X might cause a household to shift its purchasing pattern away from substitutes toward X. This shift is called the substitution effect of a price change. Everything works in the opposite direction when a price rises, ceteris paribus. When the price of a product rises, that item becomes more expensive relative to potential substitutes and the household is likely to substitute other goods for it. Income and Substitution Effects The Substitution Effect 30 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE 6.5 Income and Substitution Effects of a Price Change For normal goods, the income and substitution effects work in the same direction. Higher prices lead to a lower quantity demanded, and lower prices lead to a higher quantity demanded. Income and Substitution Effects 31 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education As in output markets, households face constrained choices in input markets. They must decide 1. Availability of jobs 2. Market wage rates 3. Skills they possess In essence, household members must decide how much labor to supply. The choices they make are affected by: Household Choice in Input Markets The Labor Supply Decision 1. Whether to work 2. How much to work 3. What kind of a job to work at 32 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education Trading one good for another involves buying less of one and more of another, so households simply reallocate money from one good to the other. “Buying” more leisure, however, means reallocating time between work and nonwork activities. For each hour of leisure that you decide to consume, you give up one hour’s wages. Thus, the wage rate is the price of leisure. Household Choice in Input Markets The Price of Leisure is the Wage 33 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education labor supply curve A curve that shows the quantity of labor supplied at different wage rates. Its shape depends on how households react to changes in the wage rate. Income effect: as the household earns higher income it also buys more leisure (so less work). Substitution effect: opportunity cost of leisure increases (higher forgone wage) so household works more. Household Choice in Input Markets Income and Substitution Effects of a Wage Change 34 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education  FIGURE 6.7 Two Labor Supply Curves When the substitution effect outweighs the income effect, the labor supply curve slopes upward (a). When the income effect outweighs the substitution effect, the result is a “backward-bending” labor supply curve: The labor supply curve slopes downward (b). Household Choice in Input Markets Income and Substitution Effects of a Wage Change 35 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education Just as changes in wage rates affect household behavior in the labor market, changes in interest rates affect household behavior in capital markets. ↑ i = ↑ cost of current consumption = ↑ savings (substitution effect) ↑ i = less savings needed to reach a specific target amount = ↓ savings (income effect) Most empirical evidence indicates that saving tends to increase as the interest rate rises. In other words, the substitution effect is larger than the income effect. financial capital market The complex set of institutions in which suppliers of capital (households that save) and the demand for capital (firms wanting to invest) interact. Household Choice in Input Markets Saving and Borrowing: Present versus Future Consumption 36 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education We now have a rough sketch of the factors that determine output demand and input supply. (You can review these in Figure II.1.) In the next three chapters, we turn to firm behavior and explore in detail the factors that affect output supply and input demand. A Review: Households in Output and Input Markets 37 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education budget constraint choice set or opportunity set diamond/water paradox financial capital market homogeneous products labor supply curve law of diminishing marginal utility marginal utility (MU) perfect competition perfect knowledge real income total utility utility utility-maximizing rule R E V I E W T E R M S A N D C O N C E P T S 38 of 38 PART II The Market System: Choices Made by Households and Firms © 2012 Pearson Education Indifference curve Marginal rate of substitution Preference map A P P E N D I X R E V I E W T E R M S A N D C O N C E P T S