Lecture 4: Demand, Supply and Equilibrium

1. Lecture 4: Demand, Supply and Equilibrium Required Text: Chapter 2

2. Law of Demand • When price of a good goes up, people buy less of that good • Leads to downward sloping demand curve

3. Demand versus Quantity Demanded • Quantity Demanded • Amount of a good consumed at a given price • Change in price means a change in quantity demanded • Movement along the demand curve • Demand • A family of numbers that lists the quantity demanded corresponding to each possible price • Demand Schedule • Demand Curve

4. Demand Schedule and Demand Curve • Demand Schedule - Refers to the demand table that shows quantity demanded at each price • Demand Curve - Graph illustrating demand - Graphical representation of the demand schedule • Price on the vertical axis • Quantity demanded on the horizontal axis • Demand Equation • Qd = (price, income, tastes and preferences, expectations, and prices of other goods)

5. Changes in Demand • Price change does not lead to change in demand • Change in anything other than price lead to demand changes - Entire curve shifts • Income • Price of related goods • Substitutes • Complements • Taste (preference) • Sales Tax • Number of consumers

6. Shifting Demand • Fall in Demand • Decision made by demanders to buy a smaller quantity at each given price • Leftward shift of demand curve • Rise in Demand • Decision made by demanders to a buy a larger quantity at each given price • Rightward shift of demand curve

7. Sales Tax Example • Sales Tax – A tax imposed on consumers • Paid directly to the government • Does not affect the price • Consumers pay “Price plus sales tax” • Less desirable to buy the taxed good or service at every given price • Demand shifts downward and to the left

8. Effect of a Sales Tax on Demand • A new law requires $0.25 sales tax per cup of coffee

9. Shape of the Demand Curve • Steeply-sloped demand curve • Large change in price leads to small change in quantity demanded • Flat demand curve • Small change in price leads to large change in the quantity demanded • Important to producers of goods and services

10. Econometrics • Statistical techniques used by economist to resolve questions about slopes of various demand curves • Based on direct observations in marketplace • Ex. Demand for murder • Ex. Demand for reckless driving • Wide scope of economics • Allows for other investigations as well

11. Market (Aggregate) Demand • Aggregate quantity of a good demanded by all consumers in a community (market) at each given price • The aggregate or market demand is obtained by the horizontal summation of all individual consumer’s demand curves. • Similar to the individual demand curve - Slopes downward

12. Market (Aggregate) Demand • Suppose, there are 10,000 SB coffee consumers in Lubbock • Each individual consumer’s demand for SB coffee is the same

13. Law of Supply • When the price of a good goes up, the quantity supplied goes up • Leads to a upward sloping supply curve

14. Supply versus Quantity Supplied • Quantity Supplied • Amount of a good that suppliers will provide at a given price • Changes if the price changes • Movement along the curve • Supply • Family of numbers giving the quantities supplied at each price • Change in anything other than price changes supply • Shifts the entire curve

15. Changes in Supply • Supply Equation • Qs =  (price, expectations, input prices, prices of other goods, technological change, number of producers) • Rise in Supply • Increase in quantities that supplier will provide at each price • Rightward shift of supply • Fall in Supply • Decrease in quantities that supplier will provide at each price • Leftward shift of supply

16. Changes in Supply • Price change does not lead to change in supply • Factors that lead to supply changes - Entire curve shifts • Production costs • Improvement in production technology • Change in the wage rate • Changes in the Prices of other goods (subs. or comps.) • Excise Tax • Number of Producers

17. Excise Tax Example • The government imposes a tax on producers • Producers pay the tax directly to the government • Price does not change, but the cost • Less desirable to produce the taxed good or service at every given price • Supply shifts to the left and upward

18. Effect of an Excise Tax on Supply • An excise tax of $0.25 per cup of coffee

19. Market (Aggregate) Supply • Aggregate quantity of a good supplied by all producers in a community (market) at each given price • The aggregate or market supply is obtained by the horizontal summation of all individual producer’s supply curves. • Similar to the individual producer’s supply curve – Market supply curve slopes upward

20. Market (Aggregate) Supply • Suppose, there are 10 SB coffee sellers in Lubbock • Each individual seller’s supply for SB coffee is the same

21. Market Equilibrium • Actual price and Quantity determined by interactions between demanders (consumers) and suppliers (sellers) • Demanders cannot purchase more than suppliers willing to sell • Suppliers cannot sell more than demanders willing to buy

22. Equilibrium Point • Point where the market demand and supply curves intersect • Price at which quantity demanded equals quantity supplied • Demanders and suppliers are satisfied • Able to behave as one wants to, taking market prices as given

23. Market Equilibrium for SB Coffee • Equilibrium price – $1.00 per cup • Equilibrium quantity – 30,000 cups per day

24. Changes in the Equilibrium Point • The only way that anything can affect the equilibrium price and quantity is by causing a shift in either the supply curve or the demand curve • Never look at price and quantity • Look at the effect of the change has on demand curve and/or supply curve • The factors that shifts the demand and supply curves affect the equilibrium price and quantity

25. The Effects of Supply and Demand Shifts Landsburg, Price Theory and Applications, 7th edition

26. Effect of Sales Tax • Sales tax of x¢ per item causes equilibrium price to fall by some amount less than x¢ per item • Price to suppliers not same as price to demanders (price plus sales tax)

27. Effect of Excise Tax • Excise tax of x¢ per item causes the equilibrium price to rise by some amount less than x¢ per item • Price to suppliers (price minus excise tax) not same as price to demanders

28. Comparing Two Taxes • Economic Incidence – the division of a tax burden according to who actually pays the tax • Legal Incidence – the division of a tax burden according to who is required under the law to pay the tax • The economic incidence of a tax independent of its legal incidence • Ex. Social Security tax

29. A Sales Tax versus an Excise Tax Landsburg, Price Theory and Applications, 7th edition

30. Aggregated Effects of a Demand Curve Shift (for example change in income) Price S D D’ P1 P0 Q Q0 Q1

31. Firm’s response to increased demand • What steps could a firm manager take to react to a shift in the demand curve to the right for an agricultural/food product? • For a competitive (atomistic) firm manager • Knowledge of the increase in demand is first seen by a noticed increase in price received. • Usual reaction is to increase output. • Other firm managers see that above normal profits are being earned and enter the market thus putting some upward pressure on input costs. • The increased production lower prices to an equilibrium price (where price = average cost) that is somewhat higher than the initial price.

32. Firm’s response to increased demand … • For the firm in monopolistic competition • the firm manager (remember the firm is a price maker) would first be aware of the increase in demand by an increase in sales or product orders. • The firm’s reaction would be to increase output and/or increase price. • Seeing the above normal profits, other firms would enter and increase the supply. • The firm would experience a weakened demand for its product with the resulting equilibrium price a little higher that the initial price. • This higher price is due to the increased average costs.

33. Firm’s response to increased demand • For the oligopolistic firm manager • The increase in demand would be recognized by an increase in sales/orders. • Reaction would be to increase output and price. • Entry is possible, but more difficult. • With entry, demand would weaken. The resulting price is not predictable.

34. Impacts of Large Decline in Demand in Alternative Market Models

35. Domestic Demand vs. Export Demand • Consideration of demand for the farm commodity must consider total demand where total demand equals domestic demand plus export demand. • Domestic food demand is fairly stable with little change from year to year. However, droughts and other disasters that occur in foreign countries can create large swings in foreign demand from year to year. • Question • What can be the major result of these often-unexpected shifts in foreign demand?

36. Agricultural/Food Sector Trends • Moving from atomistic markets towards monopolistic competition: • How: creating differentiation: regional (California fruit), branding (Dole, green giant, Del Monte) • Why: more alternative marketing strategies • For example rice, bananas, tomatoes, lettuce, beef?