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Industrial Organization & Perfect Competition. Perfectly Competitive Markets Structure Assumptions. Many buyers and sellers Homogeneous product or output Note: these first two assumptions imply that the perfectly competitive firm is a price taker. - PowerPoint PPT Presentation
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1
Industrial Organization & Perfect Competition
2
Perfectly Competitive Markets Structure Assumptions
Many buyers and sellers Homogeneous product or output
– Note: these first two assumptions imply that the perfectly competitive firm is a price taker.
– P(x) = P* = where is the demand for the individual firm’s output.
– Also note that if P(x) is just P*, then mr=P*, too.
“Free” entry and exit Full and symmetric information
3
Perfectly Competitive Markets
Every demander is a price-taker (no buyer can influence the price).
Every supplier is a price-taker (no seller can influence the price).
The market price is known to all potential buyers and sellers and anyone who wishes to trade at that price can do so.
4
An Example
Jonathan’s farm is perfectly competitive and uses the inputs shown to produce the quantities of apples indicated on the table.
Jonathan's Apple Farm Production Function
Apples (tons/year)
Land (acres)
Labor (hired)
Proprietor's time (hours)
0 100 0 1,10050 100 2,500 1,100
100 100 3,700 1,100150 100 5,000 1,100200 100 6,800 1,100250 100 10,000 1,100300 100 15,000 1,100350 100 27,000 1,100
5
Production Detail
Apple Farm Production Function (detail)
Apples (tons/year)
Land (acres)
Labor (hired)
Proprietor's time (hours)
200 100 6,800 1,100210 100 7,320 1,100220 100 7,900 1,100230 100 8,530 1,100240 100 9,220 1,100250 100 10,000 1,100260 100 10,800 1,100
Here is some finer detail regarding the apple farm.
6
Factor Prices
Jonathan is a factor price taker.
Use these factor prices to build the cost tables.
Prices
Labor's time $8.00 per hourOwner's time $12.00 per hourRent $124.00 per acre
7
CostsJonathan's Apple Farm Costs
Apples (tons/year) Land
Hired Labor
Proprietor's time Total Cost
Average Cost
Marginal Cost
(midpoint formula)
0 12,400 0 13,200 25,60050 12,400 20,000 13,200 45,600 912 296
100 12,400 29,600 13,200 55,200 552 200150 12,400 40,000 13,200 65,600 437 248200 12,400 54,400 13,200 80,000 400 400250 12,400 80,000 13,200 105,600 422 656300 12,400 120,000 13,200 145,600 485 1,360350 12,400 216,000 13,200 241,600 690
8
Finer Cost DetailsJonathan's Apple Farm Costs (detail)
Apples (tons/year) Land
Hired Labor
Proprietor's time Total Cost
Average Cost
Marginal Cost
(midpoint formula)
200 12,400 54,400 13,200 80,000 400210 12,400 58,560 13,200 84,160 401 440220 12,400 63,200 13,200 88,800 404 484230 12,400 68,240 13,200 93,840 408 528240 12,400 73,760 13,200 99,360 414 588250 12,400 80,000 13,200 105,600 422 632260 12,400 86,400 13,200 112,000 431
9
Graph of Jonathan’s Cost Curves
The marginal cost of each ton of apples is shown as the red line.
The average cost is shown as the blue line.
Notice that the marginal cost = average cost at average cost’s minimum.
Jonathan's Cost Functions
0
100
200
300
400500
600
700
800
900
1,000
0 100 200 300 400
Apples (tons/year)
$/t
on
Average Cost Marginal Cost (midpoint formula)
10
Profit Maximization Profit () = total revenue(tr) - total cost(tc). Profit depends on the firm’s output level (x). So… (x) = tr(x) - tc(x) Define
– marginal revenue (mr) = tr/x– marginal cost (mc) = tc/x
NOTE: Since we have a perfectly competitive firm P=mr for all levels of production.
11
Profit Maximization General rules for profit maximization: If x* maximizes , then
– mr = mc at x*– x* is a profit max and not a profit min – at x* it’s worth operating
Reminder: since the firm is perfectly competitive, P=mr for all values of x.
12
Jonathan’s Profit and Loss Suppose the market
price is $600/ton. The vertical
difference between Jonathan’s total revenue and total cost curve is his profit.
The profit maximum occurs at 240 tons/year.
Total Cost and Revenue
0
50,000
100,000
150,000
200,000
250,000
300,000
0 50 100 150 200 250 300 350 400
Apples (tons/year)
$
Total Cost
Total Revenue
Maximum Profit, market price= marginal cost
Total Cost, slope=marginal cost
Total Revenue, slope=market price
13
Finding Profit Maximizing Points Using The Marginal Cost Curve
Jonathan will supply apples to the market in increasing quantities as the price rises.
The points on the marginal cost curve correspond to profit maximizing quantities at two different market prices.
The quantity supplied at a market price of $600/ton is (about) 240 (black dot).
Consider another market price, P=1,200 and note that x* increases.
Marginal Cost of Apples
0
200
400
600
800
1,000
1,200
1,400
1,600
0 100 200 300 400
Apples (tons/year)
Pri
ce (
$/to
n)
mc
mr when P=600
mr when P=1,200
14
Finding the Value of Profit - Case A
If market price is P*, then the firm supplies x* where mr=mc.
Total Revenue=OACQ*
Total Cost=OBDQ*Note: use the atc curve to get the value of total costs by multiplying atc by x*
Profit = tr-tc=BACD
P* = mr
mcatc
A
B
C
D
OQuantityx*
P
15
Finding the Value of Profit - Case B
If market price is P*, then the firm supplies x* where mr=mc.
Total Revenue=OBDQ*
Total Cost=OBDQ*
Profit = tr-tc=0
Note: economic profit = 0
P* = mr
mc atc
B D
OQuantityx*
P
16
Finding the Value of Profit - Case C If market price is P*, then the firm
supplies x* where mr=mc. Total Revenue=OACQ* Total Cost=OBDQ*
Profit = tr-tc = -ABDCNote: Profits are negative. They are loses.
Should firm continue to operate? Good question. Now need to look at where the average variable cost curve is. Recall: produce at a loss provided tr vc orp avc
Since P>avc at x*, firm should produce x*.
P* = mr
mc atc
BD
OQuantityx*
A C
P
avc
17
The Firm’s Supply Curve
An individual perfectly competitive firm’s supply curve (the srsfirm) is its marginal cost curve above its average variable cost curve.
For a perfectly competitive firm, choosing the output at which market price equals marginal cost maximizes profits.– Remember, it’s really mr=mc at x*, but since the
firm is a price taker, P=mr all the time, so P=mc at x*.
18
Jonathan’s Supply Curve At the market price
indicated on the vertical axis, profit maximizing apple production is given by the marginal cost curve, which is Jonathan’s supply of apples curve.
The supply curve is the the marginal cost curve above average variable cost because profit maximizing behavior means increasing production until marginal cost = market price.
Single Farm Supply of Apples
0
200
400
600
800
1,000
1,200
1,400
1,600
0 100 200 300 400
Apples (tons/year)
Pri
ce
($
/to
n)
19
Total Costs and Economic Profits
Total costs include fixed costs, variable costs (at market prices) and the opportunity cost of owned factors (such as the owner’s time, land, and equipment owned by the business).
Economic profits are the difference between total revenue from sales and total costs, as defined above.
20
Back to Jonathan’s Farm...
The apple market is competitive. Jonathan cannot control the price of
apples. Consider, for the moment, a price of
say $528/ton now To profit maximize Jonathan produces
until P (=mr) = mc
21
Jonathan’s Economic Profit and Loss
At the market price of $528, the profit maximizing apple production is the highlighted line.
Apple Farm Profits (detail)
Apples (tons/year) Total Cost
Total Revenue
Marginal Cost
Marginal Revenue = Market
PriceEconomic
Profits200 80,000 105,600 25,600210 84,160 110,880 440 528 26,720220 88,800 116,160 484 528 27,360230 93,840 121,440 528 528 27,600240 99,360 126,720 588 528 27,360250 105,600 132,000 632 528 26,400260 112,000 137,280 25,280
22
Graph of Jonathan’s Revenue and Cost
The vertical difference between Jonathan’s total revenue and total cost curves is his economic profits.
The slope of the total cost line (marginal cost) is equal to the slope of the total revenue line (marginal revenue = market price)
Total Cost and Revenue
0
50,000
100,000
150,000
200,000
250,000
0 50 100 150 200 250 300 350 400
Apples (tons/year)
$
Total Cost Total Revenue
Maximum Profit, market price= marginal cost
Total Cost, slope=marginal cost
Total Revenue, slope=market price
23
Graph of Jonathan’s Economic Profits
The chart at the right shows that Jonathan’s economic profits are maximized at apple production where the market price is equal to the marginal cost (230 tons/year).
Profits are maximized when marginal cost is as close as possible to market price, without exceeding it.
The slope of economic profits = zero at the profit maximum.
Economic Profits (detail)
25,000
25,500
26,000
26,500
27,000
27,500
28,000
200 210 220 230 240 250 260
Apples (tons/year)
$
24
Accounting Profits
Accounting profits are defined as total sales revenue (the same as total revenue in the economic profits definition) minus operating costs (costs of goods sold + administrative and sales costs for those who know some accounting).
Accounting Profits = Sales Revenue - Accounting Costs
25
Did Jonathan Make Accounting Profits?
The blue line in the table illustrates that Jonathan makes an accounting profit of $40,800 when the apple price is $528/ton.
Accounting Profits vs. Economic Profits (detail)
Apples (tons/year)
Total Revenue
Accounting Costs
Accounting Profits Total Costs
Economic Profits
200 105,600 66,800 38,800 80,000 25,600210 110,880 70,960 39,920 84,160 26,720220 116,160 75,600 40,560 88,800 27,360230 121,440 80,640 40,800 93,840 27,600240 126,720 86,160 40,560 99,360 27,360250 132,000 92,400 39,600 105,600 26,400260 137,280 98,800 38,480 112,000 25,280
26
Economic Profits
Economic profits are the difference between total revenue and total costs.
Economic total costs include the opportunity costs of all inputs to the production process–in particular, the opportunity costs of the owner’s time and physical capital (equipment and space).
27
Reconciling Economic and Accounting Profits
The table to the right shows that Jonathan’s economic profits equal his accounting profits minus the opportunity cost of his time.
Thus, when the price of apples is $528/ton and 230 tons/year are sold, economic profits = $27,600
Reconciling Accounting and Economic Profits (detail)
Apples (tons/year)
Accounting Profits
- Opportunity Cost of
Jonathan's Time
= Economic Profits
200 38,800 13,200 25,600210 39,920 13,200 26,720220 40,560 13,200 27,360230 40,800 13,200 27,600240 40,560 13,200 27,360250 39,600 13,200 26,400260 38,480 13,200 25,280
28
Question 1
At a market price of $440/ton for apples, what is the optimal annual production of apples?
Use the data on your handout to answer this question.
29
Answer 1
Marginal cost = market price = $440/ton at a production level of 210 tons/year.
This is the profit maximizing level of output when the market price is $440/ton.
30
Question 2
At a market price of $440/ton for apples, what are Jonathan’s accounting and economic profits?
31
Answer 2
Total revenue = $440 x 210 = $92,400. Total costs = $124 x 100 (land) + $8.00
x 7,320 (labor) + $12.00 x 1,100 (proprietor’s time) = $84,160 .
Economic profits = total revenue - total costs = $92,400 - $84,160 = $8,240.
32
Answer 2 (continued)
Total revenue = $440 x 210 = $92,400. Accounting costs = $124 x 100 (land) + $8.00
x 7,320 (labor) = $70,960. Accounting profits = total revenue -
accounting costs = $92,400 - $70,960 = $21,440.
Economic profits = accounting profits - opportunity cost of owner’s time = $21,440 - $13,200 = $8,240.
33
Question 3
At a market price of $400/ton for apples, what are Jonathan’s accounting and economic profits?
34
Answer 3
Optimal production = 200 tons/year. Total revenue = $400 x 200 = $80,000. Economic profits = total revenue - total
costs = $80,000 - $80,000 = 0. Accounting profits = total revenue -
accounting costs = $80,000 - 66,800 = 13,200.
35
Question 4
Should Jonathan continue to operate the apple farm if the market price of apples is $400/ton?
36
Answer 4
Jonathan’s economic profits are zero when the market price of apples is $400/ton ($0.20/pound, about the current price wholesale price for first quality fresh apples).
Jonathan just recovers the opportunity cost of his time ($13,200), so he is indifferent between producing apples and taking a job at $12/hour.
37
Producers Surplus Revisited Producers surplus measures the gain to the firm from
selling all units at the market price. Producers surplus is the supply-side equivalent of
consumers surplus. Total producers surplus = the area above the marginal
cost curve and below the market price = economic profits + fixed costs.
Incremental producers surplus = the difference between the market price and the marginal cost of the given unit of production.
38
Jonathan’s Producers Surplus Jonathan’s total
producers surplus, when the market price is $528, is the sum of his economic profits ($27,600) and his fixed costs ($25,600) = $53,200.
Jonathan's Producers Surplus
0
200
400
600
800
1,000
1,200
1,400
1,600
0 100 200 300 400
Apples (tons/year)
Pri
ce
($
/to
n)
Market Price = $528
Producers surplus = area above the marginal cost curve, below the market price = $53,200
39
Producers Surplus and Economic Profits
Producers surplus is not equal to economic profits.
Producers surplus includes fixed costs. Economic profits = producers surplus -
fixed costs. Producers surplus = economic profits +
fixed costs.
40
The Market Supply Curve
The market supply curve is the sum of the quantities supplied by each seller at each market price.
Market supply, thus reflects the marginal costs of each of the producers in the market.
This is Short Run Market Supply (SRS)
41
Supply Curve for a New York Apple Farm
The data used to construct Jonathan’s supply curve were representative of the typical New York State apple farm.
The supply curve for a single apple farm is shown to the right.
Single Farm Supply of Apples
0
200
400
600
800
1,000
1,200
1,400
1,600
0 100 200 300 400
Apples (tons/year)
Pri
ce
($
/to
n)
It is the same as the supply curve we have been using, based on the marginal cost curve of a single farm.
42
Market Supply Curve: Horizontal Summation
Farm A’s Supply of Apples
0
200
400
600
800
1,000
1,200
1,400
1,600
0 100 200 300 400
Apples (tons/year)
Pri
ce (
$/to
n)
Farm B’s Supply of Apples
0
200
400
600
800
1,000
1,200
1,400
1,600
0 100 200 300 400
Apples (tons/year)
Pri
ce (
$/to
n)
At a price of $1000/ton, add Farm A’s supply to Farm B’s supply to get market supply (about 560 tons/year). Add over all farms.
The market supply curve is the horizontal summation of the firms’ supply curves.
43
Short Run Equilibrium - Summary The firm is profit maximizing - no desire at
current market price to change the quantity supplied.– Firm is on its short run supply curve
Market Demand = Short run Market Supply– No tendency for market price to change
Note: number of firms fixed, technology given and firm’s capital fixed.
Get: (P*, X*, x*) Firms can have +/0/- profit.
44
Profit Signal
When profit in the short run is positive there are firms at the margin that want to enter the market and it is assumed that they can.
When profit in the short run is negative there are firms at the margin that want to exit the market and it is assumed that they will.
45
Long Run Equilibrium
All the short run equilibrium properties. But also…no firms wish to exit the market
nor do firms want to enter. Get: (P*, X*, x*, N*) Note: For there to be neither entry or exit,
need economic profit to be zero. This is a long run equilibrium requirement. Otherwise the number of firms in the market will still be in flux.
46
Long Run Equilibrium Position Profit max implies that mr=lrmc at x*. Zero profit implies P=lratc at x*. Since the firm is perfectly competitive, P=mr at all values
of x. By substitution, P=lratc at x* and P=lratc at x*. Therefore lrmc=lratc at x*. This implies that x* is at the minimum of the typical firm’s
lratc. x* is at MES. P* must be the price consistent with the minimum value on
the lratc curve. N* and X* determined by position of market demand.
47
Long Run Equilibrium Picture
lratc
xx*X*
P* P* mr
SRS w/N*
D
X
A a
typical firmmarket
48
Steps to Draw The Picture?
Doesn’t matter how you draw it, as long as you draw it correctly in the end.
Draw-a-person test.
49
What’s not ok...
50
Increases in Demand
When demand increases and is expected to remain at the increased level, the short run response is to move along the short run supply curve--higher price and greater quantity supplied.
The long run response is to have entry in the market, movement along the long run supply curve--price returns to the minimum average total cost and quantity supplied increases.
51
Long Run Adjustment Picture
lratc
xx*X*
P* P* mr
SRS w/N*
D
X
A a
typical firmmarket
D new
P’ P’ mr’B
srmc
sratc
b
X’ x’
52
Long Run Equilibrium Picture
lratc
xx*X*
P* P* mr
SRS w/N*
D
Q
A a
typical firmmarket
D new
P’ P’ mr’B
srmc
sratc
b
X’ x’
SRS w/N**
C
X**
LRS
53
Long Run Supply in the Market
Both points A and C in the previous picture are long run equilibrium points.
Point B is a temporary short run equilibrium point.
If you connect all points like A and C you get the market long run supply curve in a perfectly competitive market.
X*
P*
SRS w/N*
D
X
A
D new
P’B
X’
SRS w/N**
C
X**
LRS
54
Long Run Supply in the Market The long run supply curve in
the market is horizontal at the long run equilibrium price P*.
P* is sometimes called the “normal price.”
P* is the price consistent with the typical firm’s minimum long run average total cost.
Note: important assumption is that the position of the firm’s cost curve is unaffected by entry (or exit) of firms in the market.
X*
P*
SRS w/N*
D
X
A
D new
P’B
X’
SRS w/N**
C
X**
LRS
55
Example: Long Run Supply in the System-fixer Market
The market demand for system installations is shown by the blue line in the graph.
The market is very much larger than firm’s at the efficient scale, so we expect competitive conditions to prevail.
The long run supply (in red) reflects the technological and competitive conditions in the market: surviving firms must operate at the scale of firm B at a minimum average total cost of $26/installation.
Short run supply is shown in brown.
Market for System Installations
0
5
10
15
20
25
30
35
40
45
50
0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000
Quantity (Installations/week)
Pri
ce (
$/in
stal
lati
on
)Demand
Long Run Supply
Short Run Supply
56
Question
How many firms are there in the long run in the system-fixer market?
57
Answer
Firms with the efficient scale do 8 installations per week at an average total cost of $26/installation.
At $26/installation the market demand is 8,000 installations per week.
Therefore, there are 1,000 firms in the market.
58
Increase in Demand in the System-fixer Market
Demand increases in the market as indicated by the new (black) demand curve.
The short run response is an increase in price with not much additional quantity supplied (point A), movement along the short run supply curve.
The long run response is a return to the original price of $26/installation and an expansion of quantity supplied along the long run supply curve (point B).
Increase in Demand
0
5
10
15
20
25
30
35
40
45
50
0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000
Quantity (Installations/week)
Pri
ce (
$/in
stal
lati
on
)Demand
Long Run Supply
Short Run Supply
New Demand
A
B
59
Question
What would be the long run result of a fall in demand for system installations when the quantity demanded at $26/installation is 4,000.
60
Answer
Now, only 500 firms operating at the minimum efficient scale will survive.
The industry will shrink by exit of some system fixer firms. Of the original 1,000 firms, only 500 survive.
61
External Economies and Diseconomies of Scale
If the industry exhibits no external economies or diseconomies of scale, then the industry long run supply curve is perfectly elastic (horizontal). The industry grows by replicating firms at the efficient scale. Entry and exit leaves the position of cost curves intact. This is called a constant cost industry.
If the industry exhibits external diseconomies of scale, then the industry long run supply curve is upward sloping. The minimum average total cost of all firms in the industry rises as the size of the market grows. This is called an increasing cost industry.
If the industry exhibits external economies of scale, then the industry long run supply curve is downward sloping. The minimum average total cost falls as the size of the industry grows. This is called a decreasing cost industry.
62
Constant Cost Industry
When we draw the long run supply curve as a horizontal line, we are asserting that there are no external economies or diseconomies of scale.
Lack of economies or diseconomies of scale means that growth of the industry doesn’t foster technological improvements and doesn’t change the prices of inputs.
63
External Diseconomies of Scale
When an industry long run supply curve slopes upward, the industry exhibits external diseconomies of scale.
This can occur because the prices of the inputs rise as the industry expands.
This can also occur because the industry becomes “congested” and the minimum average total cost at the efficient scale rises.
Quantity
Pric
e
Long run supply with external diseconomies of scale in the industry
64
Examples of Long Run Supply Curves that Slope Up As a competitive industry grows its demand for certain
specialized factors increases (information systems specialists in the accounting service industry, fabrication equipment in the microprocessor industry).
Increased demand for specialized factors means that the equilibrium price of these factors will increase (movement along a factor supply curve--increased quantity and increased price of the factor).
So as the industry (not the firm) grows, the price of these specialized factors increases and the minimum average total cost rises.
Thus, the long run supply curve slopes upward.
65
Long Run Competitive Equilibrium - Reviewed
The firms in a perfectly competitive market are in long run equilibrium when– Quantity supplied = Quantity demanded at the current
market price.– Firm’s are profit maximizing so that marginal revenue
(= Price) = marginal cost for all firms in the market.– Price = minimum average total cost for all firms in the
market, implying zero economic profit.– No firm wants to enter the market.– No firm currently in the market wants to exit.
66
Why are there zero economic profits in the long run? Zero economic profits means that all factors used in
production make exactly their opportunity cost. Purchased factors receive their market price, which is
equal to their opportunity cost. Owned factors receive the same compensation that they
would receive in their next best use, which is also equal to their opportunity cost.
Thus, no firm wants to enter the market because it cannot make any more money than it is currently making.
Similarly, no firm wants to leave the market because it cannot make any more money in any other business.
67
Performance Efficiency:
– Allocative efficiency: (look at market) The level of output traded is allocatively efficient if it maximizes net social surplus.
– Productive efficiency: (look at the firm) The firm’s output level is productively efficient if it is at the minimum of the firm’s long run average total cost curve, that is, if it is at least as large as minimum efficient scale of production.
Equity: – Is the outcome of the allocatoin process fair?
Equitable? Just?
68
Long Run Competitive Equilibrium - Performance
Efficiency:– The market equilibrium is allocatively efficient. That is, at
X*, net social surplus is maximized.– Each firm is productively efficient. That is each firm
operates at, at least, minimum efficient scale. Each firm operates at the minimum of its long run average total cost curve.
Equity: Is the outcome of the competitive process fair? Equitable? Just? – Good questions that we do not answer here and now.
69
Allocative Efficiency - Proof
If X* is allocatively efficient, then net social surplus should be as high as it can feasibly be.
Net Social Surplus = $TBsociety - $TCsociety
When net social surplus is as high as it can be, $MBsociety = $MCsociety
Question: Is the outcome of the competitive process allocatively efficient?
70
Answer Demand=Supply at X*. Demand represents $marginal benefit. Supply represents $marginal cost. So…marginal benefit equals marginal cost at
X*.
So…net social surplus is maximized at X*. There is no transaction among the buyers
and sellers that improves the welfare of at least one person without reducing the welfare of at least one person.
71
Productive Efficiency - Proof Profit max implies that mr=lrmc at x*. Zero profit implies P=lratc at x*. Since the firm is perfectly competitive, P=mr at all
values of x. By substitution, P=lratc at x* and P=lratc at x*. Therefore lrmc=lratc at x*. This implies that x* is at the minimum of the typical
firm’s lratc. x* is at MES. P* must be the price consistent with the minimum
value on the lratc curve.