Unit7_Feb2015.pdf

Funded by the Institute for New Economic Thinking with additional funding from Azim Premji University and Sciences Po

7THE FIRM AND ITS CUSTOMERS

HOW A PROFIT-MAXIMISING FIRM PRODUCING A DIFFERENTIATED PRODUCT INTERACTS WITH ITS CUSTOMERS.You will learn:

What the product demand curve is.

What the firms marginal cost is.

What a differentiated product is.

How a firm without close competitors chooses the price and quantity that maximises its profits, and can increase its profits through product selection and advertising.

What the gains from trade are and how they are distributed between consumers and the firm.

What the elasticity of demand is, how it affects the firms price and profit margin, and how an economic policy maker could use this information in the design of tax and competition policy.

February 2015 beta

See www.core-econ.org for the full interactive version of The Economy by The CORE Project. Guide yourself through key concepts with clickable figures, test your understanding with multiple choice

questions, look up key terms in the glossary, read full mathematical derivations in the Leibniz supplements, watch economists explain their work in Economists in Action and much more.

Courtesy of Federal Archives, Germany, Photo: Erich Krueger

coreecon | Curriculum Open-access Resources in Economics 2

pile it high and sell it cheap was the motto of Jack Cohen, who founded Tesco in 1919. Tesco is now the market leader in the UK grocery market, with higher profits than any other retailer in the world except Walmart. Keeping the price low as Cohen recommended is one possible strategy for a firm seeking to maximise its profits: the profit on each item is small, but the low price may attract so many customers that total profit is high. Other firms may adopt quite different strategies; Apple sets high prices for iPhones and iPads, increasing its profits by charging a price premium, rather than lowering prices to reach more customers. For example, between April 2010 and March 2012, profit per unit on Apple iPhones was between 49% and 58% of the price. During the same period, Tescos operating profit per unit was between 6.0% and 6.5%.

A firm needs information about demand to decide what price to charge: how much potential consumers are willing to pay for its product. Figure 1 shows the demand curve for Apple-Cinnamon Cheerios, a ready-to-eat breakfast cereal introduced by the company General Mills in 1989. In 1996, the economist Jerry Hausman used data on weekly sales of family breakfast cereals in US cities to estimate how the quantity of cereal customers would wish to buy, per week in a typical city, would vary with the price per pound. You can see from Figure 1 that if the price were $3, for example, customers would demand 24,000 pounds of Apple-Cinnamon Cheerios. The lower the price, the more customers wish to buy.

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Figure 1. Estimated demand for Apple-Cinnamon Cheerios.

Source: Adapted from Figure 5.2 of Hausman, J. 1996. Valuation of New Goods under Perfect and Imperfect Competition. In: Timothy F. Bresnahan and Robert J. Gordon, 1996. The Economics of New Goods. Chicago: University of Chicago Press, pp. 207-248.

UNIT 7 | THE FIRM AND ITS CUSTOMERS 3

INTERACT

Follow figures click-by-click in the full interactive version at www.core-econ.org.

If you were the manager at General Mills, how would you choose the price for Apple-Cinnamon Cheerios in this city, and how many pounds of cereal would you produce? Suppose that the unit costthe cost of producing each poundof Apple-Cinnamon Cheerios is $2. Then the calculation you need is:

Profit = (price unit cost) quantity = (P 2) Q

Figure 2 shows the isoprofit curves for different choices of price and quantity. Just as indifference curves join points in a diagram giving the same level of utility, isoprofit curves join points that give the same level of profit. You could make $60,000 profit by selling 60,000 pounds at a price of $3, or 20,000 pounds at $5, or 10,000 pounds at $8, or in many other ways. The darkest blue curve shows all the possible ways of making $60,000 profit. The lightest blue line shows the choices of price and quantity where profit is zero: if you set a price of $2, you would be selling each pound of cereal for exactly what it cost you to produce, making no profit whatever the amount you sold. So the zero-profit line is horizontal, joining all the points where P = 2.


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Figure 2. Isoprofit curves for the production of Apple-Cinnamon Cheerios.

Source: Isoprofit data is illustrative only, and does not reflect the real-world profitability of the product.


Of course you would like both price and quantity to be as high as possible, to maximise your profit. But you know from the demand curve that if you choose a high price you will only be able to sell a small quantity; and if you want to sell a large quantity, you must choose a low price. The only feasible choices are the points in the diagram on or below the demand curve in Figure 3: we call these points the feasible set. Figure 3 shows you how to find the profit-maximising choice of price and quantity: the highest isoprofit curve you can reach while remaining in the feasible set is the middle one, which is tangent to the demand curve. Your best strategy is to choose point E: you should produce 14,000 pounds of cereal, and sell it at a price of $4.40 per pound.

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Figure 3. The profit-maximising choice of price and quantity for Apple-Cinnamon Cheerios.

Source: Isoprofit data is illustrative only, and does not reflect the real-world profitability of the product. Demand curve data from Hausman, as above.

7.1 THE PRODUCT DEMAND CURVE

for any product that consumers might wish to buy, the product demand curve is a relationship that tells you the number of items (the quantity) they will buy at each possible price. Lets think about a market for a particular model of car. To keep things simple, imagine that there are 100 potential consumers who would each buy one car of this type, today, if the price were low enough.


Each consumer has their own willingness to pay (WTP) for a car, which depends on how much they personally value it (given that they have the resources to buy it). A consumer will buy a car if the price is less than, or equal to, that persons WTP. Suppose we line up the consumers in order of WTP, highest first, and plot a graph to show how the WTP varies along the line (Figure 4). Then if we choose any price, say P = $3,200, the graph shows the number of consumers whose WTP is greater than or equal to P. In this case, 60 consumers are willing to pay $3,200 or more, so the demand for cars at a price of $3,200 is 60.

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Figure 4. The demand for cars (per day).

If P is lower, there is a larger number of consumers willing to buyso the demand is higher. Demand curves are often drawn as straight lines, as in this example, although there is no reason to expect them to be straight in reality: we saw that the demand curve for Apple-Cinnamon Cheerios was not straight. But we do expect demand curves to slope downward: as price rises, the quantity demanded by consumers falls. Conversely, when the available quantity is low, it can be sold at a high price. This relationship between price and quantity is sometimes known as The Law of Demand.

TEST YOUR UNDERSTANDING

Test yourself using multiple choice questions in the full interactive version at www.core-econ.org.


7.2 PRODUCTION: THE FIRMS COST FUNCTION

a car manufacturer deciding how many cars to produce, and what price to set, must take into account the costs of production.

There are many costs of producing and selling cars. The firm needs premisesa factoryequipped with machines for casting, forging, assembling and welding car bodies. It may rent them, from another firm perhaps, or raise financial capital in order to invest in premises and equipment for itself. Then it must purchase the raw materials and components, and pay production workers to operate the equipment. Other workers will be needed to manage the production process and market and sell the finished cars.

The firms ownersthe shareholderswould not be willing to invest in the firm if they could make better use of their money by investing and earning profits elsewhere. What they could receive if they invested elsewhere, per dollar of their investment, is termed the opportunity cost of capital. One component of the cost of producing cars is the amount that has to be paid out to shareholders to cover the opportunity cost of capitalthat is, to induce them to continue to invest in the assets the firm needs to produce cars.

The more cars the firm produces, the higher its total costs will be. The upper panel of Figure 5 shows how total costs might depend on the quantity of cars, Q, produced. This is the firms cost function, C(Q).

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AC at B= slope of line OB= 3,600

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Figure 5. The firms cost function and average costs.


Some costs may not vary with the number of cars: for example, once it has decided on the size of factory and invested in equipment, the premises and equipment costs will be the same irrespective of output. These are called fixed costs. So when Q = 0, the only costs are the fixed costs, F. As Q increases, costs rise: the firm needs to employ more production workers. At point A, 20 cars are produced (we call this Q0) costing $88,000 (we call this C0). When the firm operates at this scale, the average cost of producing a car is C0 divided by Q0, which is shown by the slope of the line from the origin to A: average cost is $88,000/20 = $4,400. We have also plotted the average cost at point A on the lower panel.

As output rises above A total costs rise, but the average costthe cost per car produced falls: the fixed costs are shared between more cars. When average costs fall as output increases, we say that the firm has increasing returns to scale or economies of scale. At point B, with output of 40 cars, the total cost is $144,000 so the average cost has fallen to $3,600.

Point B is where the average cost is lowest. When production increases further, beyond point B, the line showing the average cost gets steeper again. The average cost rises; at these higher levels of production the firm has decreasing returns to scale (sometimes called diseconomies of scale). At point D, 64 cars are produced and the average cost has risen to $3,960. For example, this might happen if the firm has to increase the number of shifts per day on the assembly line to raise output. Average costs might increase if it has to pay overtime rates, and equipment breaks down more frequently.

If we calculate the average cost at every value of Q, we can draw the average cost (AC) curve in the lower panel of Figure 5. At low levels of production the average cost is decreasing (the firm has increasing returns to scale)so the AC curve slopes downward. The average cost is lowest at point B. After that the AC curve slopes upward, corresponding to decreasing returns to scale.

Figure 6 shows how to find the marginal cost of a car: that is, the cost of producing one more car. Suppose the firm is producing 20 cars at point A. The total cost is $88,000. The marginal cost is the cost of increasing output from 20 to 21. This would increase total costs by an amount which we call C (delta C), equal to $2,000. You can see from the triangle drawn at A that the marginal cost is equal to the slope of the cost function at that point. We have plotted the marginal cost at point A on the lower panel of Figure 6.


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Figure 6. The marginal cost of a car.

Now look at point D, where Q = 64. The cost function is much steeper there. The marginal cost of producing an extra car is higher at point D, at which C = $5,520. At point B, the curve is steeper than at A, but flatter than at D: the marginal cost is $3,600. If you look at the shape of the whole cost function you can see that when Q = 0 it is quite flat, so the marginal cost is low. As the quantity of output increases, the cost function gets steeper, and the marginal cost gradually rises.

By calculating the marginal cost at every value of Q, we can fill in the whole of the marginal cost curve in the lower panel of Figure 6. Remember that for each value of Q, the marginal cost is the cost of increasing output from Q to Q+1, which corresponds to the slope of the cost function. As Q increases the slope of the cost function rises steadily, so the graph of marginal cost is an upward-sloping line. LEIBNIZ 11 defines mathematically the concepts of average and marginal cost.

LEIBNIZ

For mathematical derivations of key concepts, download the Leibniz boxes from www.core-econ.org.


Now look at the shapes of the AC and MC curves. You can see that at values of Q where the AC is greater than the MC, the AC curve is downward-sloping, and it is upward sloping where AC is less than MC. This is not just a coincidence: it happens whatever the shape of the total cost function. If the marginal costthe cost of producing one more caris less than the average cost, then producing one more car will lower the average cost of producing cars. And if the marginal cost is greater than the average cost, producing one more car will raise the average cost.

This means the two curves cross at a point where the AC is flat (the slope is zero). At point B, where the average cost is lowest, the average and marginal costs are equal.

DISCUSS 1: THE COST FUNCTION FOR APPLE-CINNAMON CHEERIOS

Of course, the cost function in Figure 5 is not the only possible shape for a cost function. For Apple-Cinnamon Cheerios, we assumed the cost of producing every pound of cereal was equal to $2, irrespective of the quantity produced, corresponding to constant returns to scale. Try drawing the cost function for this case. You should find that it is a straight line through the origin. What do the marginal and average costs functions look like??

The economists Rajindar and Manjulika Koshal studied the cost functions of public universities in the US. They estimated the marginal and average costs of educating graduate and undergraduate students in 171 public universities in the academic year 1990-1, and found increasing returns to scale. They also found that the universities benefitted from economics of scope: that is, there were cost savings from producing several productsgraduate education, undergraduate education, and researchtogether.


DISCUSS 2: COST FUNCTIONS FOR UNIVERSITY EDUCATION

Below you can see the average and marginal costs per student for the year 1990-1 that Koshal and Koshal calculated from their research.

STUDENTS MC ($) AC ($) TOTAL COST ($)

Undergraduates

2,750 7,259 7,659 21,062,2505,500 6,548 7,348 40,414,0008,250 5,838 7,038

11,000 5,125 6,727 73,997,00013,750 4,417 6,417 88,233,75016,500 3,706 6,106 100,749,000

STUDENTS MC ($) AC ($) TOTAL COST ($)

Graduates

550 6,541 12,140 6,677,0001,100 6,821 9,454 10,399,4001,650 7,102 8,6722,200 7,383 8,365 18,403,0002,750 7,664 8,249 22,648,7503,300 7,945 8,228 27,152,400

1. Explain how you can tell from the data that returns to scale are increasing for both graduates and undergraduates.

2. Using the data for average costs, find the missing figures in the total cost columns.3. Plot the marginal and average cost curves for undergraduate education on

a graph with costs on the vertical axis, and the number of students on the horizontal axis. On a separate diagram plot the equivalent graphs for graduates.

4. What are the shapes of the total cost functions for undergraduates and graduates? You could sketch them using what you know about MC and AC; alternatively you could plot them more accurately using the numbers in the Total Cost columns. (Hint: they are not straight lines.)

5. What are the main differences between the universities cost structures for undergraduates and graduates? Can you think of any explanations for the shapes of the graphs you have drawn?


7.3 SETTING THE PRICE

not all cars are the same. Cars are differentiated products. Each make and model is produced by just one firm, and has some unique characteristics of design and performance that differentiate it from the cars made by other firms.

Like the producer of Apple-Cinnamon Cheerios, the car manufacturer chooses the price, P, and the quantity of cars to produce, Q, taking into account its production costs, and what it knows about demand for its own particular type of car. The firms profit is the difference between its revenue (the price multiplied by quantity sold) and its total costs, C(Q):

Profit = price quantity total costs = PQ C(Q)

Equivalently, it is the number of units of output multiplied by the profit per unit, which is the difference between the price and the average cost:

Profit = Q(P C(Q)/Q)

This calculation gives us what is known as the economic profit. Remember that the cost function includes the opportunity cost of capitalthe payments that must be made to the owners to induce them to hold shares, which are referred to as normal profits. Economic profit is the additional profit above the minimum return required by shareholders.

Figure 7 shows the isoprofit curves for the car manufacturer whose cost function is shown in Figure 6. The curves look similar to those for Cheerios in Figure 2, but there are some differences because the car manufacturers cost function has a different shape. The lightest blue curve shows the zero-economic-profit curve: the combinations of price and quantity for which economic profit is equal to zerobecause the price is just equal to the average cost at each quantity.


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Figure 7. Isoprofit curves for the car manufacturer.

Since the price is equal to the average cost at every point on the zero-economic-profit curve, it is identical to the average cost curve that we drew in Figure 6. Remember that the slope of the average cost curve depends on the difference between average and marginal cost. The marginal cost curve is the upward-sloping line in Figure 7. When the quantity is low, average cost is high so the price must be high just for the firm to break even. Then as we saw before, the average cost falls as quantity increases until we reach point B, and rises again where the marginal cost is greater than the average cost. So the zero-economic-profit curve slopes downward initially, and then upward when quantity is high.

The darker blue curves show higher levels of profit: in each case profit is the same at every point on the curve; and profit is higher on the curves further from the origin. At point G, for example, where the firm makes 28 cars, the price is $9,520 but the average cost is $3,806. The firm would be making a profit of $5,714 on each car, and its total profit would be $160,000. As quantity increases the shape of the isoprofit curve follows the shape of the average cost curve, but they gradually get closer to each other.

DISCUSS 3: LOOKING AT ISOPROFIT CURVES

Why do the higher isoprofit curves get closer to the average cost curve as quantity increases?


We already know that at point B, where average cost is lowest, MC is equal to AC. So on the zero-economic-profit curve, the price is lowest at the point where it is equal to marginal cost. You can see in Figure 7 that each of the isoprofit curves has the same property: they slope down when the price is greater than the marginal cost, and up when the price is less than the marginal cost. And the lowest price on each isoprofit curve is equal to the marginal cost at that point.

The explanation for this property of isoprofit curves is similar to the one for the AC curve. At point G,the price is much higher than the marginal cost, so if you made one more car, and sold it at this price, your profit would rise . For profit to stay constant, the price would have to be lower: hence the curve slopes down. At point H, however, the price is lower than the marginal cost so if you made one more car you would need to raise the price to keep profit constant. In EINSTEIN 1 we work out a formula for the slope of an isoprofit curve, which shows that it depends on the difference between the price and the marginal cost. To find out how to calculate the slope of the isoprofit curve using calculus, see LEIBNIZ 12.

EINSTEIN 1

Calculate the slope of the isoprofit curve. Suppose that a firm is currently selling Q cars at a price P, with a marginal cost of MC, and that P is greater than MC. If the firm increased its quantity by 1, but kept the price the same, profit would increase by (P-MC). The increase in profit would be (P-MC)/Q per car. So to keep profit constant, the price of each car would need to decrease by this amount.

This means that the isoprofit curve slopes downward. The slope of the curve is the amount by which the price has to fall to keep profit constant when Q rises by 1::

Slope = Fall in price, P = (P-MC)/Q

The same calculation works when MC is greater that P, except that in this case an increase in price is required to keep profit constant when quantity rises by 1. The isoprofit curve slopes upward with slope equal to (MC-P)/Q.

In Figure 8 we have added the demand curve for this type of car. What is the best choice of price and quantity for the manufacturer? The only feasible choices are the points on or below the demand curve, shown by the red-shaded area on the diagram. To maximize profit the firm should choose the tangency point E, where it reaches the highest possible isoprofit curve.


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Figure 8. The profit-maximising choice of price and quantity for the car manufacturer.

The profit-maximising price and quantity are P* = $5,440 and Q* = 32, and the corresponding profit is $56,000. LEIBNIZ 13 shows how to find an equation for the firms profit-maximising price using calculus, and demonstrates that the equation can be interpreted in different ways.

DISCUSS 4: THE FIRMS CHOICE OF P AND Q

6. Suppose the firm sets P* = $5,440, but produces 50 cars instead of 32. What will happen? How will its profit be affected?

7. Is it feasible for the firm to choose Q* = 32 and P = $5,400? What would happen to its profit in this case? (You should be able to calculate it exactly.)

8. Suppose the firm decides to switch from P* = $5,440 and Q* = 32 to a higher price. Assuming that it chooses its output to make as much profit as possible at the new price, explain how this will affect: The quantity of cars produced. Total costs. Marginal cost. The profit.


7.4 GAINS FROM TRADE

when the firm sets its profit-maximising price P* = $5,440 and sells Q* = 32 cars per day, the 32nd consumer, whose willingness to pay is $5,440, is just indifferent between buying and not buying a car, so that buyers gain from trade or surplus is equal to zero. But other buyers were willing to pay more. You can see from Figure 9 that the 10th consumer, whose WTP is $7,200, makes a surplus of $1,760, shown by the vertical red line in the diagram. The 15th consumer has WTP $6,800 and hence a surplus of $1,360. To find the total surplus obtained by consumers, we can add together the surplus of each buyer: this is shown on the diagram by the red-shaded trianglethe area between the demand curve and the line where price is P*. This measure of the consumers gains from trade is known as the consumer surplus.

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You can think of this quantity as the difference between the total that consumers actually paid at the price of $5,440, and the total amount the seller could have collected if he had been able to charge each consumer, separately, the maximum they would have been willing to pay. Firms sometimes try to tailor their prices to particular groups of consumersairlines charging last-minute travellers higher fares, for exampleso as to capture some of the surplus that would otherwise go to the buyers.


Similarly, the firm makes what is called a producer surplus on each car sold. The marginal cost of the 20th car is $2,000. By selling it for $5,440 the firm gains $3,440, shown by a vertical purple line in the diagram. To find the total producer surplus, we add together the surplus on each car produced: this is the purple-shaded area on the diagram.

Producer surplus is the difference between the firms daily revenue when it sells 32 cars at $5,440, and the lesser amount it would collect if consumers had all of the bargaining powerin which case each buyer would bargain the price down to the firms marginal cost of that particular car and the firm would get no surplus on any car. (This is a hypothetical case; consumers in such a market never have this type of bargaining power in practice.)

Recall that in Unit 5 we looked at voluntary exchange contracts between Angela and Bart in which both parties gained; although the division of the gains from exchange depended on bargaining power. Here the consumer surplus for the 32 buyers, and the producer surplus for the firm, are measures of their gains from trade in this market. The car producer has more power than its consumers because it is the only seller of this type of car. It can set a high price and obtain a high share of the gains, knowing that consumers with high valuations of the car have no alternative but to accept. An individual consumer has no power to bargain for a better deal because the firm has many other potential customers.

Notice that the firm makes a surplus on every car produced, including the 32nd and last one: the price is greater than the marginal cost of making another car. This means that the allocation of cars is not Pareto efficient. There are other consumers who could be made better off, without reducing the firms profits, because they are willing to pay more for a car than it would cost the firm to produce it. So the potential gains from trade in the market for this type of car have not been exhausted.

If the firm had chosen point F instead, where the marginal cost line crosses the demand curve, producing Q0 cars and selling them at a price equal to the marginal cost of the last car produced, consumers who were willing to buy at the higher price would each obtain a higher surplus due to the decrease in price, and additional consumers would also obtain a surplus. This point represents a Pareto efficient outcome, with no further potential gains from trade. On the other hand the firm does better, at the expense of consumers, by choosing point E.


7.5 THE ELASTICITY OF DEMAND

the firm maximises profit by choosing the point where the slope of the demand curve is equal to the slope of the isoprofit curve. We can think of its decision in the same way as we did for the student in Unit 3, who faced a trade-off between exam marks and hours of free time. Here, the demand curve presents the firm with a trade-off between price and quantity: the slope shows how much the price will have to be lowered to sell another car. The slope of the isoprofit curve represents the trade-off the firm is willing to make: how much the price can be lowered if another car is sold, without reducing profit. Profit is maximised at the point where the two trade-offs are in balance.

So a firms choice of price and quantity depends on how steep the demand curve is: in other words, how much consumers demand for a good will change if the price changes. The price elasticity of demand is a measure of the responsiveness of consumers to a price change: it is defined as the percentage change in demand that would occur in response to a 1% increase in price. For example, suppose that when the price of a product increases by 10%, we observe a 5% fall in the quantity sold. Then we can calculate the elasticity as follows:

Elasticity = % change in demand/% change in price = 5/10 = 0.5

The price elasticity of demand is not the same as the slope of the demand curve, but they are closely related. If the demand curve is quite flat, the quantity changes a lot in response to a change in price, so the elasticity is high. Conversely, a steep demand curve corresponds to a low elasticity. In EINSTEIN 2 we show you the precise relationship between elasticity and the slope of the demand curve.

Figures 10 and 11 show how the elasticity of demand affects the car manufacturers pricing decisions. Figure 10 represents a situation of highly elastic demand. The demand curve is flat, so small changes in price make a big difference to sales. The profit maximising choice is point E. You can see that the profit marginthe difference between the price and the marginal cost at this pointis relatively small. This means that the quantity of cars it chooses to make is not far below the quantity that would maximise total gains from trade, at point F.


EINSTEIN 2

Calculate the elasticity of demand. Suppose that, when the price of a product increases by 5%, we observe a 10% fall in the quantity sold. Then the elasticity of demand is 2 (10 divided by 5).

A flatter demand curve has a lower slope, so a higher elasticity.

The diagram below shows how the elasticity of demand can be calculated from the slope of the demand curve:

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% change in P = 100 x P/P % change in Q = 100 x Q/Q

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=

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Figure 11 shows the decision of a firm with the same costs of car production, but inelastic demand for its product. In this case the profit margin is high, and the quantity is low. When the price is raised, many consumers are still willing to pay. The firm maximises profits by exploiting this situation, obtaining a higher share of the surplus, but the result is that fewer cars are sold and the unexploited gains from trade are high.


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4,000

3,000

2,000

1,000

0

Demand curve

Marginal cost


Profit margin

E

F

Quantity

0 10 20 30 40 50 60 70 80 90 100 110 120

Figure 10. A firm facing elastic demand.

Demand curve

Pri

ce, m

argi

nal c

ost

($)

10,000

9,000

8,000

7,000

6,000

5,000

4,000

3,000

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Marginal cost


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0 10 20 30 40 50 60 70 80 90 100 110 120

Figure 11. A firm facing inelastic demand.

These examples illustrate that the lower the elasticity of demand, the more the firm will raise the price above the marginal cost, achieving a high profit margin. A low demand elasticity gives the firm the power to raise the price without losing many customers. EINSTEIN 3 shows you that the profit margin as a proportion of the price, which we call the markup, is inversely proportional to the elasticity of demand. To find out how to calculate elasticities using calculus, see LEIBNIZ 14.


EINSTEIN 3

We can find a formula for the size of the price markup chosen by the firm, which shows that the markup is high when the elasticity of demand is low:

From Figure 8 we can see that at the point chosen by the firm, the slope of the isoprofit curve is equal to the slope of the demand curve. We know that the slope of the demand curve is related to the price elasticity of demand: elasticity = P/Q x 1/slope.

Rearranging this formula: slope of demand curve = P/Q x 1/elasticity

We have also calculated: slope of isoprofit curve = (P-MC)/Q

When the two slopes are equal: (P-MC)/Q = P/Q x 1/elasticity

Rearranging this gives us: (P-MC)/P = 1/elasticity

(P-MC)/P is the difference between price and marginal cost as a proportion of the price, which is a measure of the markup. So we have shown that the firms markup is inversely proportional to the elasticity of demand.

7.6 USING DEMAND ELASTICITIES IN GOVERNMENT POLICY

measuring elasticities of demand is useful to policy makers as well as firms choosing prices. If the government puts a tax on a particular good, the tax will raise the price paid by consumers, so the effect of the tax will depend on the elasticity of demand. If demand is highly elastic, the tax will reduce sales. That may be what the government intends: for example, governments use taxes on tobacco to discourage smoking because it is harmful to health. But if a tax causes a large fall in sales, it also reduces the potential tax revenue. This suggests that a government wishing to raise tax revenue should choose to tax products with inelastic demand.

Several countries, including Denmark and France, have recently introduced taxes intended to reduce the consumption of unhealthy food and drink. A 2014 international study found worrying increases in adult and childhood obesity since 1980. In 2013, 37% of men and 38% of women worldwide were overweight or obese.


In North America, the figures are 70% and 61%, but the obesity epidemic does not only affect the richest countries; the corresponding rates were 59% and 66% in the Middle East and North Africa.

Matthew Harding and Michael Lovenheim used detailed data on the food purchases of US consumers to estimate elasticities of demand for different types of food, to investigate the effects of food taxes. They divided food products into 33 categories and used a model of consumer decision-making to examine how changes in their prices would change the share of each category in consumers expenditure on food, and hence the nutritional composition of the diet, taking into account that the change in the price of any product would change the demand for that product and other products too. The table below shows the prices and elasticities for some of the categories.

You can see in Figure 12 that the demand for lower calorie milk products is the most price responsive. If their price increased by 10%, the quantity purchased would fall by 19.72%. Demand for snacks and candy is quite inelastic, which suggests that it may be difficult to deter consumers from buying them.

CATEGORY TYPE CALORIES PER SERVINGPRICE PER

100G ($)

TYPICAL SPENDING PER WEEK

($)

PRICE ELASTICITY OF DEMAND

1 Fruit and vegetables 660 0.38 2.00 1.128

2 Fruit and vegetables 140 0.36 3.44 0.830

15 Grain, Pasta, Bread 1540 0.38 2.96 0.854

17 Grain, Pasta, Bread 960 0.53 2.64 0.292

28 Snacks, Candy 433 1.13 4.88 0.270

29 Snacks, Candy 1727 0.68 7.60 0.295

30 Milk 2052 0.09 2.32 1.793

31 Milk 874 0.15 1.44 1.972

Figure 12. Price elasticities of demand for different types of food.

Source: Extracted from Harding, M., and Lovenheim, M. 2013. The effect of prices on nutrition: comparing the impact of product-and nutrient-specific taxes. SIEPR Discussion Paper No. 13-023: LINK.


DISCUSS 5: ELASTICITY AND EXPENDITURE

The table also shows the spending per week in each category of a US consumer whose total expenditure on food is $80, with typical spending patterns across food categories.

1. Suppose that the price of category 30, high-calorie milk products, increased by 10%: By what percentage would his demand for high-calorie milk products fall? Calculate the quantity he consumes, in grams, before and after the price

change. Calculate his total expenditure on high-calorie milk products before and after

the price change. You should find that expenditure falls.2. Now choose a category for which the price elasticity is less than 1, and repeat the

calculations. In this case you should find that expenditure rises.

Harding and Lovenheim examined the effects of 20% taxes on sugar, fat and salt. A 20% sugar tax, for example, would increase the price of a product that contains 50% sugar by 10%. A sugar tax was found to have the most positive effect on nutrition. It would reduce sugar consumption by 16%, fat by 12%, salt by 10%, and calorie intake by 19% .

DISCUSS 6: FOOD TAXES AND HEALTH

Food taxes intended to shift consumption towards a healthier diet are controversial. Some people think that individuals should make their own choices, and if they prefer unhealthy products, the government should not interfere. But what if you make dietary choices you subsequently regret? You prefer to eat healthy food, but are sometimes weak-willed, acting in the short-term against your own long-term preferences. Do you think this would justify taxes on sugar, fat, and salt?


7.7 MONOPOLY POWER AND COMPETITION

our analysis of the firms pricing decisions might be applied to any firm producing and selling a product that is in some way different from that of any other firm. In the 19th century the French economist Augustin Cournot carried out a similar analysis using the example of bottled water from a mineral spring which has just been found to possess salutary properties possessed by no other. Cournot referred to this as a case of monopolya market in which there is only one seller. He showed, as we have done, that the firm would set a price greater than the marginal production cost.

PAST ECONOMISTS

AUGUSTIN COURNOT

Augustin Cournot (1801-1877) was a French economist, now most famous for his model of oligopoly (a market with a small number of firms). Cournots 1838 book Recherches sur les Principes Mathmatiques de la Thorie des Richesses (Research on the Mathematical Principles of the Theory of Wealth) introduced a new mathematical approach to economics, although he feared it would draw on me the condemnation of theorists of repute. Cournots work influenced other 19th century economists such as Marshall and Walras, and established the basic principles we still use to think about the behaviour of firms. Although he used algebra rather than diagrams, Cournots analysis of demand and profit maximisation is very similar to ours.

While the definition of monopoly seems straightforward, it really depends on how we define the relevant market. There may be only one seller of the water from a particular spring, but many sellers in the market for bottled water. We usually reserve the label monopoly for cases where there are no close substitutesno similar products available from other firms. The domestic water supply, for example, is typically a regional monopoly: residents can obtain water only from one local supply company.


We think of cars, and bottled water, as examples of differentiated products rather than monopoly. So far, our analysis of pricing applies to both. But, unlike the monopolist, the producer of a differentiated product may face competition from other firms producing close substitutes for its own brand.

Markets with differentiated products reflect differences in the preferences of consumers. People who want to buy a car are looking for different combinations of characteristics. A consumers willingness to pay for a particular model will depend not only on its characteristics, but also on the characteristics and prices of similar types of car sold by other firms.

For example, Figure 13 shows the purchase prices of a three-door 1.0 litre hatchback in the UK in January 2014 that a consumer could find on a price comparison web site:

FORD FIESTA

VAUXHALL CORSA

PEUGEOT 208

TOYOTA IQ

11,917

11,283

10,384

11,254

PRICE

Figure 13. Car purchase prices in the UK, January 2014.

Source: Autotrader.com

Although the four cars are similar in their main characteristics, the website compares them on 75 other features, many of which differ between them.

When consumers are able to choose between several quite similar cars, the demand curve for each of these cars is likely to be quite flat. If the price of the Ford Fiesta, for example, were to rise, demand would fall because people would choose to buy one of the other brands instead. Conversely if the price of the Ford Fiesta were to fall, demand would increase because consumers would be attracted away from the other cars. The more similar the other cars are to a Ford Fiesta, the more responsive


consumers will be to price differences. Only those with the highest brand loyalty to Ford, and those with a strong preference for a characteristic of the Ford that other cars do not possess, would fail to respond. As we saw in the previous section, highly elastic demand means that the firm will have a relatively low price and profit margin.

In contrast, the manufacturer of a very specialised type of car, quite different from any other brand in the market, faces little competition and hence less elastic demand. It can set a price well above marginal cost without losing customers. Such a firm is earning high rentseconomic profits over and above its costs of production similar to the first firm to introduce a new technology that we saw in Unit 2. The rents arise from its position as the only supplier of this type of car.

We expect a monopolist, with no competitors, to face relatively inelastic demand. In its relationship with potential consumers it has sufficient bargaining power to make a take-it-or-leave-it offer of a high price. Although any firm producing a differentiated product behaves in the same way as a monopolist when setting its price, it has less monopoly power: that is, less ability to benefit from setting a high price. The more it is exposed to competition from substitutable products, the more elastic will be its demand curve, and the lower its profit margin and rents.

7.8 THE PROBLEM OF MONOPOLY POWER

the analysis in the previous section helps to explain why policymakers may be concerned about cases of monopoly: a monopolist is able to set high prices, and make high profits, at the expense of consumers. Potential consumer surplus is lost because few consumers buy, and because those who do buy pay a high price.

The way in which the policymaker should respond to this situation will depend on the reason for the existence of a monopoly. If one firm is becoming dominant in a market, governments may intervene to promote competition. In 2000 the European Commission prevented the proposed merger of Volvo and Scania on the grounds that the merged firm would have a dominant position in the heavy trucks market in Ireland and the Nordic countries, particularly in Sweden where the combined market share of the two firms was 91%.

A particular cause for concern is that when there are only a few firms in the market they may form a cartel: a group of firms that collude to keep the price high, rather than competing with each other. By working together they can increase profits by behaving as a monopoly. A well-known example is OPEC, an association of oil-producing countries who jointly agree to limit production to maintain a high oil price. The actions of the OPEC cartel played a major role in sustaining high oil prices


at a global level following the sharp increase in oil prices in 1973 and again in 1979. We return to study the effect of the oil price shocks on inflation and unemployment in Unit 14.

While cartels between private firms are illegal in many countries, firms often find ways to cooperate in the setting of prices so as to maximise profits. Policy to limit monopoly power and prevent cartels is known as competition policy, or antitrust policy in the US. In a famous antitrust case, the US Department of Justice accused Microsoft of behaving anti-competitively by bundling its own Internet Explorer web-browser with its Windows operating system.

As the Microsoft example illustrates, dominant firms may exploit their position in ways other than setting high prices. In the 1920s an international group of companies making electric light bulbs, including Philips, Osram and General Electric, formed a cartel that agreed a policy of planned obsolescence: to reduce the lifetime of their bulbs to 1,000 hours, so that consumers would have to replace them more quickly. The growth of Walmart, the largest retailer in the world, has been controversial, but not because of its prices; instead it has been accused of reducing wages in the locality of its stores, driving smaller retailers out of the market, and using its bargaining power to reduce the profitability of its suppliers.

DISCUSS 7: MULTINATIONALS V. INDEPENDENT RETAILERS

Imagine that you are a local politician in a town where a multinational retailer is planning to build a new superstore. A local campaign is protesting that it will drive small independent retailers out of business, and thereby reduce consumer choice and change the character of the area. Supporters of the plan counter that this will only happen if consumers prefer the supermarket. Which side are you on?

Competition policy is not a solution in all cases. In domestic utilities such as water, electricity and gas, there are high fixed costs of providing the supply network, irrespective of the quantity demanded by consumers. The average cost of producing a unit of water, electricity or gas will be very high unless the firm operates at a large scale. If a single firm can supply the whole market at lower average cost than two firms, the industry is said to be a natural monopoly.

In the case of a natural monopoly, a policymaker may choose to regulate the firms activities, aiming to increase consumer surplus by limiting the firms discretion over prices. An alternative is public ownership. The majority of water supply companies


around the world are owned by the public sector, although in England and Wales in 1989, and in Chile in the 1990s, the entire water industry was privatised and regulated by a public sector agency.

7.9 PRODUCT SELECTION, INNOVATION AND ADVERTISING

the profits that a firm can achieve depend on the demand curve for its product, which in turn depends on the preferences of consumers and the competition from other firms. But the firm may be able to move the demand curve to increase profits by its selection of products, or through advertising.

When deciding what goods to produce, the firm would ideally like to find a product that is both attractive to consumers and has different characteristics from the products sold by other firms. In this case demand would be highmany consumers would wish to buy it at each priceand inelastic. Of course, this is not likely to be easy: a firm wishing to make a new breakfast cereal, or type of car, knows that there are many brands on the market already. But technological innovation may provide opportunities to get ahead of competitors. For some years after Toyota developed the first mass-produced hybrid car, the Prius, in 1997, there were very few comparable cars available. Toyota effectively monopolised the hybrid market. By 2013 there were several competing brands, but the Prius remained the market leader, with more than 50% of hybrid sales.

If a firm has invented or created a new product, it may be able to prevent competition altogether by claiming exclusive rights to produce it, using patent or copyright laws. This kind of legal protection of monopoly may help to provide incentives for research and development of new products, but at the same time limits the gains from trade. In Unit 20 we analyse intellectual property rights in more detail.

Advertising is another strategy firms can use to influence demand: it is widely used by both car manufacturers and breakfast cereal producers. When products are differentiated, the firm can use advertising to inform consumers about the existence and the characteristics of its product, to attract them away from its competitors, and to create brand loyalty.

According to the analyst Schonfeld and Associates, advertising on breakfast cereals in the US is about 5.5% of total sales revenueabout three and a half times higher than the average for manufactured products. The data in Figure 14 is for the highest-selling 35 breakfast cereal brands sold in the Chicago area in 1991 and 1992. The graph shows the relationship between market share and quarterly expenditure on advertising. If you investigated the breakfast cereals market more closely, you


would see that market share is not closely related to price. But it is clear from Figure 14 that the brands with the highest share are also the ones that spend the most on advertising. The economist Matthew Shum analysed cereal purchases in Chicago using this data, and showed that advertising was more effective than price discounts in stimulating demand for a brand. Since the most well-known brands were also the ones spending most on advertising, he concluded that its main function was not to inform consumers about the product, but rather to increase brand loyalty, and encourage consumers of other cereals to switch.

6

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Corn Flakes

Cheerios

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Grape Nuts

Raisin BranQuaker Oats

0 1 2 3 4 5 6 7 8

Figure 14. Advertising expenditure and market share of breakfast cereals, Chicago, 1991-92.

Source: Shum, M. 2004. Does Advertising Overcome Brand Loyalty? Evidence from the Breakfast Cereals Market. Journal of Economics and Management Strategy, 13(2), pp. 241-272, Fig 1.

7.10 CONCLUSION

we have studied how firms producing differentiated products choose the price, and the quantity of output to produce, to maximise their profit. These decisions depend on the demand curve for the productespecially the elasticity of demandand the cost structure for producing it.

But as Figure 15 shows, firms make other decisions that influence the demand curve and the cost structure. The firm chooses the characteristics of its product through product innovation, aiming to attract consumers and differentiate itself further from its competitors, thereby reducing the elasticity of demand. And as we saw in Unit 2,


innovation in the production process may enable it to reduce its costs. If the firm can innovate successfully it can earn rents; at least in the short term until others catch up. Further innovation may be needed if it is to stay ahead. Advertising can increase demand and reduce its elasticity. As we saw in the previous unit, the firm sets the wage; and as we will see in Unit 21, the firm also spends to influence taxes and environmental regulation.

Figure 15. The firms decisions.


UNIT 7 KEY POINTS

1. The product demand curve tells you how many units consumers will buy at each price.

2. The firms marginal cost is the addition to total cost of making one extra unit of output.

3. In markets where products are differentiated

Each firm chooses its price and quantity from the feasible set given the demand for its own brand; the profit-maximising point is where the demand curve touches the highest isoprofit curve.

The firm sets a price greater than its marginal cost, which means that all the potential gains from trade are not realised.

The lower is the elasticity of demand (steeper demand curve), the higher is the firms price relative to its marginal cost, and the higher is its profit margin.


UNIT 7: READ MORE

7.1 THE PRODUCT DEMAND CURVE

The Law of DemandEvans, G. H. 1967. The Law of Demandthe Roles of Gregory King and Charles Davenant. The Quarterly Journal of Economics, 81 (3): pp. 483-492.

7.2 PRODUCTION: THE FIRMS COST FUNCTION

Economies of scale and the theory of priceThis article from The Economist explains more about economies of scale and scope: LINK.The Economist. 2008. Economies of scale and scope, 20 October.For an interesting discussion of costs, see Chapter 7 of George Stiglers book, available online: LINK.Stigler, G. 1987. The Theory of Price. New York: Macmillan.

7.6 USING DEMAND ELASTICITIES IN GOVERNMENT POLICY

Prices, nutrition and obesityThis blog illustrates one reaction to Matthew Harding and Michael Lovenheims research: LINK.Huffington Post. 2014. Theres An Easy Way To Fight Obesity, But Conservatives Will HATE It, 7 January.Harding and Lovenheims original article:Harding, M. and Lovenheim, M. 2014. The effect of prices on nutrition: comparing the impact of product-and nutrient-specific taxes (No. w19781). National Bureau of Economic Research.

7.8 THE PROBLEM OF MONOPOLY POWER

US v. MicrosoftRichard Gilbert and Michael Katz explain the source and strength of Microsofts power: LINK.Gilbert, R. J. and Katz, M. L. 2001. An economists guide to US v. Microsoft. Journal of Economic Perspectives, pp. 25-44.


Market powerJohn Vickers describes the different ways firms can exploit and maintain a dominant position in the market.Vickers, J. 1996. Market power and inefficiency: A contracts perspective. Oxford Review of Economic Policy, 12(4), pp. 11-26.The causes and consequences of Walmarts growth are discussed by Emel Basker: LINK.Basker, E. 2007. The causes and consequences of Wal-Marts growth. The Journal of Economic Perspectives, pp. 177-198.The history of the light-bulb cartel is explained in this student blog: LINK.Economics Student Society of Australia. 2012. Planned Obsolescence: The Light Bulb Conspiracy, 12 September.

7.9 PRODUCT SELECTION, INNOVATION AND ADVERTISING

The structure of strategyJohn Kay discusses the business strategies that successful companies use: LINK.Kay, J. 1993. The Structure of Strategy. Business Strategy Review, 4: pp. 1737.

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