Author Archives: Mark

A2 Economics – The Accelerator

This part of the syllabus will come up either as a multiple-choice question or part of an essay. The accelerator theory states that investment is determined by the RATE AT WHICH INCOME, AND HENCE OUTPUT, CHANGES OVER TIME. The principle states simply that unless the rate of increase in consumption is maintained, the previous level of investment will not be maintained.

This theory assumes that firms try to maintain some constant relationship between the level of output and the stock of capital required to produce that output. In other words, we assume a constant capital-output ratio which can be expressed in either physical terms or money terms. The accelerator helps us to understand how small changes in demand in one sector can be magnified and spread throughout the economy. The example below assumes that the firm starts with 8 machines each year and 1 machine wears out each year and that each machine can produce 100 units of output per year. In the second year, demand rises for capital goods rises by 200% (from 1 to 3). When the rate of growth of demand for consumer goods slows in year 4, demand for capital goods falls. In year 6 demand drops and they is no requirement for any investment.

Limitations of Accelerator:

* Firms can meet output with stocks – may not need investment
* Changes in technology may mean firms don’t need to invest in as much capital as before
* Firms need to be convinced that demand is long-term to warrant investment
* Limited supply of technology available

Adapted from CIE AS and A Level Economics Revision Guide by Susan Grant

US China Trade War – end in sight?

From The Economist YouTube channel – a good overview of the US China Trade War. After joining the WTO, China became an economic superpower. But people had expected the country to also become more like a Western capitalist economy. That didn’t happen. America now claims that China achieved its growth by not playing fair. Are those claims justified?

The Trump administration has been using tariffs or taxes on imported goods to try to force the Chinese to change their ways. In July 2018 America imposed tariffs of 25% on $34bn worth of Chinese products. That almost doubled the average tariff rate on Chinese imports from 3.8% to 6.7%. And it’s American firms that have to pay that tax. But with every increase from America, came an increase from China. Since the start of the trade war China has more than doubled its average tariff rate. America’s has tripled. The fight has become overtly political because China’s tariffs are hitting President Trump’s voter base. Many counties where Trump won in the 2016 election were here in the Great Plains and these are the counties most affected by China’s tariffs.

A2 Revision – Liquidity Preference

With the A2 multiple choice tomorrow here is a mind map on liquidity preference. The liquidity preference or the demand for money is the sum of the transactionary, precautionary and speculative demand for money. Only the speculative demand is inversely related to interest rates. It is the speculative demand that students find difficult to understand. This is money not held for transaction purposes but in place of other financial assets, usually because they are expected to fall in price.  Demand is interest elastic – i.e. is affected by changes in interest rates. Below is a mind map and some notes.

Adapted from CIE AS A Level Revision Guide by Susan Grant

Bond prices and interest rates are inversely related – Interest Rates ↑ = Bond Prices ↓ and Interest Rates ↓ = Bond Prices ↑. If a bond has a fixed return, e.g. $10 a year. If the price of a bond is $100 this represents a 10% return. If the price of the bond is $50 this represents a 20% return, i.e. the lower the price of the bond, the greater the return.

At high rates of interest, individuals expect interest rates to fall and bond prices to rise. To benefit from the rise in bond prices individuals use their speculative balances to buy bonds. Thus when interest rates are high speculative money balances are low.

At low rates of interest, individuals expect interest rates to rise and bond prices to fall. To avoid the capital loses associated with a fall in the price of bonds individuals will sell their bonds and add to their speculative cash balances. Thus, when interest rates are low speculative money balances will be high.

AS Revision – Indirect Tax

The AS multiple-choice paper is coming up and here is this graphic to explain indirect taxes – a popular question. An indirect tax will have the following effects on the market:

Indirect Tax

• The supply curve shifts vertically upwards(effectively a shift to the left) by the amount of the tax(gf) per unit. The price increases but not by the full amount of the tax. This is because of the slopes of the demand and supply curves.
• The consumer surplus is reduced from acp to agb. The portion gbhp of the old consumer surplus is transferred to government in the form of tax.
• The producer surplus is reduced from pce to fde. The portion phdf of the old producer surplus is transferred to the government in the form of tax.
• The market is no longer able to reach equilibrium, and there is a loss of allocative efficiency resulting in the deadweight lost shown by the area bcd. This represents a loss of both consumer surplus bhc and the producer surplus hcd that is removed from the market. The deadweight loss also represents a loss of welfare to an individual or group where that loss is not offset by a welfare gain to some other individual or group.

AS and A2 Macroeconomics: Internal and External Balances

In explaining the differences between internal and external balances I came across an old textbook that I used at University – Economics by David Begg. It was described as ‘The Student’s Bible” by BBC Radio 4 and I certainly do refer back to it quite regularly. Part 4 on macroeconomics has an informative diagram that shows the impact of booms and recessions on the internal and external balances.

Internal Balance – when Aggregate Demand equals Aggregate Supply (potential output). And there is full employment in the labour market. With sluggish wage and price adjustment, lower AD causes a recession. Only when AD returns to potential output is internal balance restored.

External Balance – this refers to the Current Account balance. The country is neither underspending nor overspending its foreign income. For a floating exchange rate, the total balance of payments is always zero. Since the balance of payments is the sum of the current, capital, and financial accounts, saying the current account is in balance then also implies that the sum of the capital and financial accounts are in balance.

In the diagram right the point of internal and external balance is the intersection of the two axes, with neither boom nor slump, and with neither a current account surplus nor a deficit.

The top left-hand quadrant shows a combination of a domestic slump and a current account surplus. This can be caused by a rise in desired savings or by an adoption of a tight fiscal policy and monetary policy. These reduce AD which cause both a domestic slump and a reduction in imports.

The bottom left-hand corner shows a higher real exchange rate, which makes exports less competitive, reduces export demand and raises import demand. The fall in net exports induces both a current account deficit and lower AD, leading to a domestic slump.

In a downturn a more expansionary fiscal and monetary policy can hasten the return to full employment eg. Quantitative easing, tax cuts, lower interest rates. However one could say that today it doesn’t seem to be that effective.

A2 Revision: Multiple-Choice question on shape of Total Cost curve


With the CIE A2 multiple-choice paper coming, up a popular question concerns the point on the Total Cost curve when MC, AVC, and ATC are at their lowest point. In the graph note the corresponding points on the Total Cost. They usually ask you where on the Total Cost line is the lowest point on the MC curve/AVC curve etc.

MC cuts ATC and AVC at their lowest points. The firm will supply where the price is greater than or equal to MC. Thus the individual firm’s supply curve consists of the firm’s MC curve, but only the portion above AVC . The reason for this is that where P=AVC the firm will shut down operations because they are barely covering avoidable costs.

Resource Curse – but what about ‘Trade Partner Curse’ – New Zealand’s trade with China.

I have blogged quite a few times about the ‘Resource Curse’ but what about the ‘Trade Partner Curse’? New Zealand has been renowned for its primary exports but is it a concern that a third of every dollar earned in the primary sector comes from China. Dr Robert Hamlin (University of Otago) stated that based on experience no more than 20% of revenue should be earned from one source to ensure a buffer against changes in terms of trade and the economic conditions in the favoured country of destination.

Higher Terms of Trade – would be beneficial because the country needs fewer exports to buy a given number of imports.
Lower Terms of Trade – country must export a greater number of units to purchase the same number of imports.

New Zealand which is traditionally dependant on primary exports usually faces instability which arises from inelastic and unstable global demand especially from China. By relying on the Chinese market, New Zealand exposes itself to greater risk of recessions in that market which may reduce in the demand for New Zealand products. Having numerous export markets means that there isn’t such exposure to economic volatility. Furthermore, countries that are commodity dependent or have a narrow export basket usually faces export instability which arises from inelastic and unstable global demand. The 2018-19 Ministry for Primary Industries’ Situation and Outlook report stated that from the year to June 2019 – total primary exports = $46.3bn but when you look at the breakdown from which country you get the worrying sign that more trade is going to China and less to other countries – essentially China is crowding out other markets:

China – $14.4bn
Australia – $4.5bn
USA – $4.2bn
EU – $3.1bn
Japan – $2.6bn


In 2017 China accounted for 24% of all New Zealand’s trade exports (see above). China also was the top export destination for New Zealand primary sector – 24% of primary sector exports went to China – by value:
25% of dairy,
43% of forestry,
31% of seafood and
21% of red meat.

China is taking a long-term approach to secure food supplies for its growing population by also buying NZ processing companies, giving it control of the supply chain. The reliance on China comes with risks that its economy remains strong. A downturn in their economy could have implications for New Zealand’s primary sector so it is important to have a diversified portfolio.

A2 Revision – Oligopoly and the kinked demand curve – download

With the A2 Essay paper tomorrow I thought something on the kinked demand curve might be useful. 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 to 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 Revision – Long-Run Monopolistic Competition

Monopolistic LR

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.

A2 Revision – Indifference Curves – Mindmap

With the A2 exam on Wednesday next week here are some notes on indifference curves – it is a good essay to do if you know the theory. The video below is particularly useful.

Income and Substitution Effects with Indifference Curves
Any price change can be conveniently analysed into 2 separate effects – the INCOME EFFECT and the SUBSTITUTION EFFECT.

Income effect of a price change: – when there is a fall in the price of a product, the consumer receives a real income effect and is able to buy more of this and other products in spite of the fact that nominal income is unchanged. If the consumer buys more of the good when the price falls it is a Normal good. If the consumer buys less of the good when the price falls it is seen as an Inferior good.

Substitution effect of a price change: – when there is a rise or fall in the price of a product, the consumer receives a decrease or an increase in the utility derived from each unit of money spent on the product and therefore rearranges demand to maximise utility. This is distinct from the income effect of a price change. For all products, the substitution effect is always positive such that a fall in price leads to an increase in demand as consumers realise an increase in the satisfaction they derive from each unit of money spent on the product.

Remember for normal goods, both the income and substitution effects are positive. But the income effect can be negative: if a negative income effect outweighs the positive substitution effect, this means that less is bought at a lower price and vice-versa. This good is therefore known as a Giffen good.

Giffen goods are generally regarded as goods of low quality which are important elements in the expenditure of those on low incomes. A good example is a basic food such as rice, which forms a significant part of the diet of the poor in many countries. The argument, not accepted by all economists, is that when the price of rice falls sufficiently individuals’ real income will rise to an extent that they will be able to afford more attractive substitutes such as fresh fruit or vegetables to makeup their diet and as a result they will actually purchase less rice even though its price has fallen.