Tài liệu Microeconomics for MBAs 36 pdf

Chapter 11 Firm Production under Idealized Competitive Conditions FIGURE 11.1 Demand Curve Faced by Perfect Competitors The market demand for a product part a is always downward slopin

Chapter 10 Production Costs in the

Short Run and Long Run

23

curve IQ2 The firm is producing as much as it can 150 pairs of jeans a day with an expenditure of $600 If it produces the same amount but used more labor on more

capital, it would move to a lower isoquant and a lower output level A point b on curve

IC1, for instance, the firm would lower its production level from 150 to 100 pairs of jeans per day

FIGURE 10.A3 Finding the Most Efficient

combination of Resources

Assuming the dial wage of each worker is

$100, and the daily rental on each sewing

machine is $20, an expenditure of $600 per

day will buy any combination of resources

on isocost curve IC1 The most

cost-effective combination of labor and capital is

point a, three workers and fifteen machines

At that point, the isocost curve is just

tangent to isoquant IQ2 , meaning that the

firm can product 150 pairs of jeans a day If

the firm chooses any other combination, it

will move to a lower isoquant and a lower

output level At point b (on isoquant IS1 ), it

will be able to produce only 100 pairs of

jeans a day

Of course, with increased expenditures, the firm can move to a higher isocost curve In

figure 10.A4, as the firm’s budget expands, its isocost curve shifts outward from IC1 to

IC2 to IC3 At the same time, the firm’s most efficient combination of resources increases

from a to b and then to c As expenditures on resources rise, we can anticipate that

beyond some point the increase in output will not keep pace with the increase in

expenditure; at that point the marginal cost of a pair of jeans will rise

FIGURE 10.A4 The Effect of Increased

Expenditures on Resources

An increase in the level of expenditures on

resources shifts the isocost curve outward

from IC1 to IC2 The firm’s most efficient

combination of resources shifts from point a

to point c

Chapter 10 Production Costs in the

Short Run and Long Run

24

PERSPECTIVES: Dealing with the Very Long Run

Economic analysis tends to be restricted to either the short or the long run, for one major reason For both periods, costs are known with reasonable precision In the short run, firms know that beyond some point, increases in the use of a resource (for example, fertilizer) will bring diminishing marginal returns and rising marginal costs They also know that with increased use of all resources, certain economies and

diseconomies of scale can be expected over the long run Given what is known about the technology of production and the availability of resources, economists can draw certain conclusions about a firm’s behavior and the consequences of its actions

As economists look further and further into the future, however, they can predict less about a firm’s behavior and its consequences in the marketplace Less is known about the technology and resources of the distant future In the very long run, everything is subject to change—resources themselves, their

availability, and the technology for using them The very long run is the time period during which the

technology of production and the availability of resources can change because if invention, innovation, and discovery of new technologies and resources

By definition, the very long run is, to a significant degree, unpredictable Firms cannot know today how

to make use of unspecified future advances in technology A hundred years ago firms had little idea how important lasers, satellites, airplanes, and computers would be to today’s economy Indeed, many products taken for granted today were invented or discovered quite by accident Edison developed the phonograph while attempting to invent the light bulb John Rock developed the birth control pill while studying

penicillin, Charles Goodyear’s development of vulcanization, and Wilhelm Roentgen’s invention of the x-ray—all were accidents All had economic consequences that could not have been predicted

Not all inventions or innovations are accidental, and we can know something about the very long run Firms have some idea of the value of investments in research and development Research on substitute resources can yield improvements in productivity that translate into cost reductions Research on new product designs will yield more attractive and useful products There will be failures as well—research projects that accomplish little or nothing—but over time, the rewards of research and development can exceed the costs

Because of the risks involved in research and development, some firms may be expected to fail In the very long run, they will not be able to keep up with the competition in product design and productivity The will not adjust sufficiently to changes in the market and will suffer losses The computer industry provides many examples of firms that tried to build a better machine, but could not keep pace with the rapid technological advances of competitors

Proponents of a planned economy see the uncertainty of the very long run as an argument for

government direction of the nation’s development They stress that competitors often do not know what other firms are doing Therefore they need guidance in the form of government subsidies and tax penalties

to ensure that the nation’s long-term goals are achieved

Proponents of the market system agree that it is difficult to look ahead to the very long run, but they see the uncertainties as an argument for keeping production decisio ns in the hands of firms Private firms have the economic incentive of profit to stay alert to changes in market conditions, and they can respond quickly

to changes in technology and resources Government control might slow the adjustment process

CHAPTER 11

Firm Production under Idealized

Competitive Conditions

Economists understand by the term market, not any particular market place in which things are bought and sold, but the whole of any region in which buyers and sellers are in such free intercourse with one another that the prices of the same goods tend to equality, easily and quickly

Augustin Cournot

receding chapters dealt separately with the two sides of markets, consumers and

producers We devised graphic means of representing consumer preferences (the

demand curve) and producer costs (average and marginal cost curves) This chapter brings demand and cost analysis together in order to examine the way in which individual

firms react to consumer demand in competitive markets Our focus will be on a highly

competitive market structure called perfect competition We will investigate an intriguing

question: at the limit, how much can competitive markets contribute to consumer welfare?

We will not attempt to give a full description of a real-world competitive market

setting Because markets are so diverse, such a description would probably not be very

useful Our aim is rather to devise a theoretical framework that will enable us to think about

how markets work in general, as a constructive behavioral force Although our model cannot tell much that is specific about real-world markets, it will provide a basis for predicting the

general direction of changes in market prices and output Through its analysis, we should

gain a deeper understanding of the meaning of market efficiency

Perfect competition is only one of four basic market structures The other three, and the detrimental effects of their restrictions on competition, are the subjects of following

chapters

The Four Market Structures

Markets can be divided into four basic categories, based on the degree of competition that

prevails within them that is, on how strenuously participants attempt to outdo, and avoid

being outdone by, their rivals The most competitive of the four market structures is perfect competition

P

Chapter 11 Firm Production under Idealized

Competitive Conditions

1 There are many producers in the market, no one of which is large enough to

affect the going market price for the product All producers are price takers,

as opposed to price searchers or price makers (see the Perspective on the subject below)

2 All producers sell a homogeneous product, meaning that the goods of one

producer are indistinguishable from those of all others Consumers are fully knowledgeable about the prices charged by different producers and are totally indifferent as to which producer they buy from

3 Producers enjoy complete freedom of entry into and exit from the market—

that is, entry and exit costs are minimal, although not completely absent

4 There are many consumers in the market, no one of whom is powerful enough

to affect the market price of the product Like producers, consumers are price takers

As we have seen before, the demand curve facing the individual perfect competitor is not the same as the demand curve faced by all producers The market demand curve slopes downward, as shown in Figure 11.1(a) The demand curve facing an individual producer price taker is horizontal, as in Figure 11.1(b) This horizontal demand curve is perfectly

elastic That is, the individual firm cannot raise its price even slightly above the going

market price without losing all its customers to the numerous other producers in the market

or to other producers waiting for an opportunity to enter the market On the other hand, the individual firm can sell all it wishes at the going market price Hence it has no reason to

offer its output at a lower price The markets for wheat and for integrated computer circuits,

or computer chips, are both good examples of real-world markets that come close to perfect competition

Pure Monopoly

Pure monopoly: A single seller of a product for which there are no close substitutes

Protected from competition by barriers to entry into the market The barriers to entry into the monopolist’s market will be described in the next chapter For now, we will simply note that because the monopolistic firm does not have to worry about competitors undercutting its

price, it can raise its price without fear that customers will move to other producers of the

same product or similar products All the pure monopolist has to worry about is losing

customers to producers of distantly related products

Since the monopolist is the only producer of a particular good, the downward-sloping market demand curve [Figure 11.1(a)] is its individual demand curve Unlike the perfect

competitor, the monopolistic firm can raise its price and sell less, or lower its price and sell

more The critical task of the pure monopolist is to determine the one price-quantity

combination of all price-quantity combinations on its demand curve that maximizes its

profits In this sense the pure monopolist is a price searcher The best (but not perfect) real-world examples of a pure monopoly are regulated electric-power companies, which dominate

in given geographical areas, and the government’s first-class postal system

Chapter 11 Firm Production under Idealized

Competitive Conditions

FIGURE 11.1 Demand Curve Faced by Perfect Competitors

The market demand for a product part (a) is always downward sloping The perfect competitor is on a

horizontal, or perfectly elastic, demand curve [part (b)] It cannot raise its price above the market price even slightly without losing its customers to other producers

Monopolistic Competition

Monopolistic competition is a market composed of a number of producers whose products

are differentiated and who face highly elastic, but not perfectly elastic, demand curves

A monopolistically competitive market can be recognized by the following

characteristics:

1 There are a number of competitors, producing slightly different products

2 Advertising and other forms of nonprice competition are prevalent

3 Entry into the market is not barred but is restricted by modest entry costs, mainly overhead

4 Because of the existence of close substitutes, customers can turn to other

producers if a monopolistically competitive firm raises its price Because of brand

loyalty, the monopolistic competitor’s demand curve still slopes downward; but it is

fairly elastic [see Figure 11.2)

The market for textbooks is a good example of monopolistic competition Most subjects are covered by two or three dozen textbooks, differing from one another in content, style of

presentation, and design

Chapter 11 Firm Production under Idealized

Competitive Conditions

PERSPECTIVE: Price Takers and Price Searchers

Perfect competition is an extreme degree of competition, so much so that many students are understandably concerned about its relevance They often ask, “If there are few market structures that even closely approximate perfect competition, why bother to study it?” The question is a good one and not altogether easy to answer There are few markets that come close to having numerous producers of an identical product with complete freedom of entry and exit Markets for agricultural commodities and for stocks and bonds are probably the

closet markets we have to perfect competition, but still the products are not always completely identical, and

entry and exit costs abound in most markets Even wheat sold by a Kansas wheat farmer us not always viewed the same as wheat sold by a Texas wheat farmer

How can sense be made of perfect competition? The answer is remarkably simple We know that under the conditions of competition specified, certain results follow We can logically (with the use of graphs and

mathematics) derive them, and the results are developed in this and the following chapter One conclusion drawn is that in perfect competition each firm will extend production until the marginal cost of producing the

last unit equals the price paid by the consumer That conclusion necessarily follows As we will see, it is

mathematically valid The strict (extreme) assumptions about the nature of perfect competition assure that The demanding conditions for perfect competition are rarely met We nevertheless cannot conclude that

under less demanding competitive conditions, competitive results would not be observed [see the Perspectives

on contestable markets on page 240.) For example, it may be that the number of producers is not “numerous” that the products sold by all producers are not completely “identical,” and that there are costs to moving in and

out of markets Nonetheless, individual producers may act as if the conditions of perfect competition are met

Individual producers may still act as if they have no control over market price or that there are so many other actual or potential producers that it is best to think in terms of the other producers being numerous”—in which case many of the predicted results of perfect competition may be still observed in the less-than-perfect markets

For these reasons, many economists often talk not about perfect competitors but about price takers (who may

or may not fit exactly the description of perfect competitors) Price takers are sellers who do not believe they

can control the market price by varying their own production levels They simply observe the market price and either accept it (and produce accord ingly, to the point where marginal cost and marginal revenue and price are

equal) or reject it (and go into some other business) The price taker is someone who acts as if his or her demand

curve is horizontal (perfectly elastic, more or less) He or she is therefore someone who assumes the marginal revenue on each unit sold is constant (and equal to the price)—and that the marginal revenue curve is horizontal and the same as the firm’s demand curve

The price searcher stands in contrast to the price taker Price searchers are sellers who have some control

over the market price Price searchers have monopoly power due to the fact that they can alter production and thereby market supply sufficiently to change the price The individual price searcher’s task is not simply to accept or reject the current market price, but (like the monopolist) to “search” through the various price-quantity combinations on his or her downward sloping demand curve with the intent upon maximizing profits As we will see in the following chapter, the marginal revenue and demand curves of the price searcher are no longer the same (Exactly where the monopolist’s marginal revenue curve lies in relation to the demand curve will be discussed in detail in the next chapter)

Chapter 11 Firm Production under Idealized

Competitive Conditions

FIGURE 11.2 Demand Curve Faced by a

Monopolistic Competitor

Because the product sold by the monopolistically

competitive firm is slightly different from the

products sold by competing producers, the firm

faces a highly elastic, but not perfectly elastic,

demand curve

Oligopoly

An oligopoly is a market composed of only a handful of dominant producers—as few as

two—whose pricing decisions are interdependent Oligopolists may produce either an

identical product (like steel) or highly differentiated products (like automobiles) Generally

the barriers to entry into the market are considerable, but the critical characteristic of

oligopolistic firms is that their pricing decisions are interdependent That is, the pricing

decisions of any one firm can substantially affect the sales of the others Therefore, each

firm must monitor and respond to the pricing and production decisions of the other firms in

the industry The importance of this characteristic will become clear in a following chapter

Table 11.1 summaries the characteristics of the four market structures

The Perfect Competitor’s Production Decision

As we learned earlier, the market price in a perfectly competitive market is determined by the intersection of the supply and demand curves If the price is above the equilibrium price

level, a surplus will develop forcing competitors to lower their prices If the price is below

equilibrium, a shortage will emerge, pushing the price upward [see Figure 11.3(a)] Given a market price over which it has no control, how much will the individual perfect competitor

produce?

The Production Rule: MC = MR

Suppose the price in the perfectly competitive market for computer chips $5 (P1 in Figure

11.3) For each individual competitor, the market price is given, that is, cannot be changed

It must be either accepted or rejected If the firm rejects the price, however, it must shut

down If it raises its price even slightly above the market level, its customers will move to

other competitors.) Demand, then, is horizontal at $5

Chapter 11 Firm Production under Idealized

Competitive Conditions

Table 11.1 Characteristics of the Four Market Structures

Number of Firms

Freedom of Entry

Type of Product

Example Perfect competition Many Very easy Homogeneous Wheat,

Computers, and Gold

Pure monopoly One Barred Single product Public utilities

and Postal service

Monopolistic com-

petition

Many Relatively easy Differentiated Pens,

Books, Paper, and Clothing

Oligopoly Few Difficult Either standardized

or differentiated

Steel, Light bulbs, Cereal, and Autos

_

The firm’s perfectly elastic horizontal demand curve is illustrated on the right side of

Figure 11.3 This horizontal demand curve is also the firm’s marginal revenue curve,

because marginal revenue is defined as the additional revenue acquired from selling one

additional unit Because each computer chip can be sold at a constant price of $5, the

additional, or marginal, revenue acquired from selling an additional unit must be constant at

$5

Because profit equals total revenue minus total cost (profit = TR = TC), the

profit-maximizing firm will produce any unit for which marginal revenue exceeds marginal cost

Thus the profit-maximizing firm in Figure 11.3(b) will produce and sell q 1 units, the quantity

at which marginal revenue equals marginal cost (MR = MC) Up to q1, marginal revenue is

greater than marginal cost Beyond q 1, all additional computer chips are unprofitable: the

additional cost of producing them is greater than the additional revenue acquired [with the

small “q” being used to remind you that the output individual producer in Figure 11.3(b) is a small fraction of the output for the market, designated by a capital “Q” in Figure 11.3 (a)]

Changes in Market Price

The perfectly competitive firm produces where MC = MR, both of which are equal to price Thus the amount the firm produces depends on market price As long as market demand

remains constant, the individual firm’s demand, and its price, will also remain constant If

market demand and price increase, however, the individual firm’s demand and price will also increase

Chapter 11 Firm Production under Idealized

Competitive Conditions

FIGURE 11.3 The Perfect Competitor’s Production Decision

The perfect competitor’s price is determined by market supply and demand [part (a)] As long as

marginal revenue (MR), which equals market price, exceeds marginal cost (MC), the perfect

competitor will expand production [part (b)] The profit-maximizing production level is the point

at which marginal cost equals marginal revenue (price)

FIGURE 11.4 Change in the Perfect Competitor’s Market Price

If the market demand rises from D 1 to D 3 [part (a)], the price will rise with it, from P 1 to P 3 As a

result, the perfectly competitive firm’s demand curve will rise, from d1 to d3 [part (b)]

Chapter 11 Firm Production under Idealized

Competitive Conditions

Figure 11.4 (above) shows how the shift occurs The original market demand of D1

leads to a market price of P1 [part (a)], which is translated into the individual firm’s demand,

d1 [part (b)] The firm maximizes profit by equating marginal cost with marginal revenue,

which is equal to d 1 , at an output level of q1.1

An increase in market demand to D2 leads to the higher price P2 and a higher

individual demand curve, d2 At this higher price, which equals marginal revenue, the perfect

competitor can support a higher marginal cost The firm will expand production from q 1 to

q 2 In the same way, an even greater market demand, D3, will lead to even higher output, q3,

by the individual competitor

Why does the market supply curve slope upward and to the right? The answer lies in the upward-sloping marginal cost curves confronted by individual firms (The market supply curve is obtained by horizontally adding the supply curves of individual firms.) The

individual firm’s marginal cost curves slope upward because of diminishing (marginal)

returns, a technological fact of the production process

Maximizing Short-Run Profits

Can perfect competitors make an economic profit? The answer is yes, at least in the short

run To see this point, we must incorporate the average and marginal cost curves developed

in the last chapter into our graph of the perfect competitor’s demand curve, as in Figure

11.5(b) [Figure 11.5(a) shows the market supply and demand curves.) As before, the

producer maximizes profits by equating marginal cost with price, rather than by looking at

average cost That is exactly what the perfect competitor does The firm produces q 2

computer chips because that is the point at which marginal revenue curve (which equals the

firm’s demand curve crosses the marginal cost curve At that intersection, marginal revenue

of the last unit sold equals its marginal cost If less were produced that q 1, the marginal cost would be less than the marginal revenue, and profits would be lost Similarly, by producing

anything more than q2, the firm incurs more additional costs (as indicated by the marginal

1

To prove this statement, first we note that

Q P

TR =

Then we define short-run total cost to be a function of output:

SRTC = C (Q)

Next, we define profits π to be

) Q ( C Q P SRTC

= π

Differentiating with respect to Q and equating with 0, we then obtain

dQ

) Q ( dC P

0 dQ

) Q ( dC P dQ d

=

=

−

= π

Since

dQ

)

Q

(

dC

= SRMC, profits are maximized when SRMC = P