Archive for the ‘Market Structures’ Category

A2 Revision – Price Discrimination

October 9, 2015 Leave a comment

Here is a great video from Tyler Cowen of Marginal Revolution fame in which he explains Price discrimination – Unit 2 in the CIE Economic syllabus. Price discrimination is common: movie theaters charge seniors less money than they charge young adults. Computer software companies sell to businesses and students at different rates, often offering discounts to students. These price differences reflect variations in the elasticity of demand for these different groups. When demand curves are different, it is more profitable to set different prices in different markets. We’ll also cover arbitrage and take a look at some examples of price discrimination in the airline industry

A2 Revision – Oligopoly and the kinked demand curve – download

October 2, 2015 Leave a comment

I alluded to in a previous post that one model of oligopoly revolves around how a firm perceives its demand curve. The model relates to an oligopoly in which firms try to anticipate the reactions of rivals to their actions. As the firm cannot readily observe its demand curve with any degree of certainty, it has got to estimate how consumers will react to price changes.

In the graph below the price is set at P1 and it is selling Q1. The firm has to decide whether to alter the price. It knows that the degree of its price change will depend upon whether or not the other firms in the market will follow its lead. The graph shows the the two extremes for the demand curve which the firm perceives that it faces. Suppose that an oligopolist, for whatever reason, produces at output Q1 and price P1, determined by point X on the graph. The firm perceives that demand will be relatively elastic in response to an increase in price, because they expects its rivals to react to the price rise by keeping their prices stable, thereby gaining customers at the firm’s expense. Conversely, the oligopolist expects rivals to react to a decrease in price by cutting their prices by an equivalent amount; the firm therefore expects demand to be relatively inelastic in response to a price fall, since it cannot hope to lure many customers away from their rivals. In other words, the oligopolist’s initial position is at the junction of the two demand curves of different relative elasticity, each reflecting a different assumption about how the rivals are expected to react to a change in price. If the firm’s expectations are correct, sales revenue will be lost whether the price is raised or cut. The best policy may be to leave the price unchanged.

With this price rigidity a discontinuity exists along a vertical line above output Q1 between the two marginal revenue curves associated with the relatively elastic and inelastic demand curves. Costs can rise or fall within a certain range without causing a profit-maximising oligopolist to change either the price or output. At output Q1 and price P1 MC=MR as long as the MC curve is between an upper limit of MC2 and a lower limit of MC1.

Criticisms of the kinked demand curve theory.
Although it is a plausible explanation of price rigidity it doesn’t explain how and why an oligopolist chooses to be a point X in the first place. Research casts doubt on whether oligopolists respond to price changes in the manner assumed. Oligopolistic markets often display evidence of price leadership, which provides an alternative explanation of orderly price behaviour. Firms come the conclusion that price-cutting is self-defeating and decide that it may be advantageous to follow the firm which takes the first steps in raising the price. If all firms follow, the price rise will be sustained to the benefit of all firms.

If you want to gradually build the kinked demand curve model download the powerpoint by clicking below.

A2 Economics – Teaching MC=MR with M&M’s

August 4, 2015 Leave a comment

Having just completed Perfect Competition with my A2 class I used a couple of packets of M&M’s to drum home the concept of marginal analysis MC=MR. It has always been something that students have struggled with but I am hoping this experience of creating graphs with M&M’s might help their understanding and when to use the concept.

Profit is maximised at the rate of output where the positive difference between total revenues and total costs is the greatest. Using marginal analysis, the perfectly competitive firm will produce at a rate of output where marginal revenue equals marginal cost. Marginal revenue, however, is equal to price. Therefore, the perfectly competitive firm produces at an output rate where marginal cost equals the price of output. Remember that the firm will make profits as long as the extra revenue brought in from selling the last unit of output(MR) is greater than the extra cost which is incurred in producing it(MC). Below are some of the graphs they created – subnormal profit and normal profit



A2 Economics – Teaching MC=MR with M&M’s

April 2, 2015 Leave a comment

For the last lesson before the Easter break I got students to do a variety of graphs using M&M’s. Long-run Perfect Competition, Short-run Perfect Competition, MC, AC and AVC to name just a few. A good exercise and an incentive to get them correct with the reward of eating the graph. Some creations below:


Economics of Seinfeld – Moral Hazard and Imperfect Information

March 23, 2015 Leave a comment

Here is another clip from Seinfeld which is an example of moral hazard and imperfect information.

Jerry’s car is stolen, so he rents a car. The rental company doesn’t give him the car he reserved; he gets a small economy car. They ask if he wants insurance, and he replies, “Yes, because I’m going to beat the hell out of this car.” Source: Seinfeld Economics

Micro economics leads the way

January 16, 2015 Leave a comment

Micro EconomicsThe Economist wrote in one its ‘Leaders’ that macro economists could learn a lot from their micro economist colleagues. Micro economists tend to focus more on individual markets or firms and through the use of technology are able to acquire huge amounts of data on each producing amazingly accurate forecasts of human behaviour. Rather than taking the standard textbook supply and demand, the new breed of micro economists help nudge the two into line. An example that they use is Uber – the taxi service – where prices surge during peak hours and this attracts more drivers onto the road.

Another example that The Economist use is the online book market. Research from MIT showed that used books (335 titles) typically sold for $17.50 which is 50% more than in book stores. By accessing all the readers interested in a book through the Internet you create more demand for the book which translate into higher prices. Furthermore the reader is better off as without the Internet they would not have found the book. One of the authors of the research bought a 30 year old book on pharmaceuticals online as the MIT library didn’t have it. She paid $20 for the book but was surprised to see that on the inside cover it had been priced in the second hand bookshop at $0.75.

The macro economists seem to create theoretical models before testing them against the data whilst the micro economists let computers spot patterns from the actual data.

A2 Revision: Monopolistic Competition Long-Run

November 13, 2014 Leave a comment

Monopolistic LRWith the A2 essay paper tomorrow here is a quick revision note on monopolistic competition. This is a market structure in which there are a large number of firms selling commodities which are very close substitutes. There are weak barriers to entry and firms may enter the industry with ease. Notice on the diagram that the firm initially makes supernormal profit at Q0 – at MC=MR Price = P0 and Cost = AC0. However with weak barriers to entry these profits are competed away and they now produce at Q1 where at MC=MR and the Price and Cost = AC1

Modern capitalism is characterised by a large number of ‘limited’ monopolies. They are sole suppliers of branded goods, but other firms compete with them by selling similar goods with different brand names. This is the market structure described as monopolistic competition. Thus the commodities produced by any one industry are not homogeneous; the goods are differentiated by branding and the use of trade marks. The individual firm has a monopoly position, but it faces keen competition from firms supplying very similar goods. It has, therefore, only a limited degree of monopoly power – how much depends upon the extent to which firms are free to enter the industry. Product differentiation is emphasised (some would say, created) by the practice of competitive advertising which is, perhaps, the most striking feature of monopolistic competition.

Advertising is employed to heighten in the consumer’s mind the differences between Brand X and Brand Y. It is important to realise that we are concerned with the differentiation of goods in the economic sense and not in the technical sense. Two branded products may be almost identical in their technical features or chemical composition, but if advertising and other selling practices have created different images in the consumer’s mind, then these products are different from our point of view because the consumer will be prepared to pay different prices for them.


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