Category Archives: Teaching visuals

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.
Oligopoly

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.

Using whiteboards to teach externalities graphs

I held my annual whiteboard competition with my A2 Economics class to see who could draw the best 4 graphs showing Positive and Negative Externalities of Consumption and Production. The winner this year was Fiona Leng with two highly recommended by Jemima Hodgson and Yanz Chen.

Fiona Leng

Jemima Hodgson

Yanz Chen

The externalities topic at A2 Level Economics involves being able to draw and understand four graphs. A different way of teaching this area of the course was to get students to use A3 size whiteboards so that they could practice drawing these graphs. This proved to be very successful with students for the following reasons:

  • the novelty of using whiteboards
  • if they made a mistake this could be easily rubbed out and they could start again
  • it allowed me to go around the class to correct graphs where necessary
  • students took pride in their graphs
  • the best set of graphs was posted on the econfix blog
  • students who were struggling could learn off others

Using playing cards for economics discussions

No doubt you’ve had plenty of discussions with your classes on economic issues. One of the challenges is to keep students on task and try and get contributions from all students. In order to overcome these issues I have developed a set of playing cards with certain statements on each. Students receive 8 playing cards with different assessment objectives/ skills/ elements of written work in economics – see photo below.


An exam essay question is given to students and then they debate the questions amongst themselves. However students can only speak when they play a card and they must follow what the card says – e.g. Argument, Building on someone’s point etc. This limits each student’s number of responses and makes sure the discussion helps students practice for an assessment, according to the assessment objectives. It also allows for greater contributions from other members of the class. It generally works well although at times you may have to play one of your own cards to keep students on task. I have attached a link to a document with all the statements – below. All you have to do is buy some packs of playing cards and use wide sellotape to attach statements to the cards. Be interested to know how others get on.

CARDS

Economics website for IGCSE AS A2 and IB courses

Want to learn or need assistance with Economics? Are you studying or teaching A Level Economics, Advanced Placement, or International Baccalaureate (IB)?

Help is at hand, elearnEconomics assists individuals studying Economics. This site covers a wide range of courses and individuals have the ability to customise their course or do extension work. It’s simple, easy to use and very cost effective.

eLearnEconomics is a comprehensive online economics learning resource. It is for both students AND teachers. Students study the concepts of each topic with the key notes, then review those concepts with the audio/video and flash card sections and finally test themselves in the written answer and multi-choice sections. The multi-choice section records student scores enabling them to track their progress and build their confidence leading into exams.

Teachers have the ability to monitor students progess within the teachers’ administration section. Students can be arranged into class groups and full reports generated to quickly identify problem areas. These high quality PDF reports can also be presented at parent/teacher evenings. Click the link below to access the site.

elearneconomics

Free access to elearnEconomics – ends Sunday 11th November

Just a note to say that free access ends on Sunday 11th November.

Below is a link to free access to elearnEconomics website. It includes notes, video lessons and multiple-choice questions with worked answers. It covers all aspects of IB, NCEA (NZ curriculum), Cambridge International Exams (CIE)  A levels and most university introductory courses.

Login as School Guest Members on the right hand side:

https://www.elearneconomics.com/main/login

Guest Login (Username): elearn

Guest Login (Password): economics

If you have any questions contact elearn resources:

Email: info@elearneconomics.com

Website: www.elearneconomics.com | www.rennieresources.co.nz

Free access to elearnEconomics

Below is a link to free access to elearnEconomics website. It includes notes, video lessons and multiple-choice questions with worked answers. It covers all aspects of IB, NCEA (NZ curriculum), Cambridge International Exams (CIE)  A levels and most university introductory courses.

Login as School Guest Members on the right hand side:

https://www.elearneconomics.com/main/login

Guest Login (Username): elearn

Guest Login (Password): economics

If you have any questions contact elearn resources:

Email: info@elearneconomics.com

Website: www.elearneconomics.com | www.rennieresources.co.nz

A2 Economics – using whiteboards to teach externalities

Once again with my A2 class I successfully used whiteboards to get across the concepts of positive and negative externalities. Below are the graphs done by Sarah Cheng. As I have stated before whiteboards are a very useful way of getting across difficult graphs.

The externalities topic at A2 Level Economics involves being able to draw and understand four graphs. A different way of teaching this area of the course was to get students to use A3 size whiteboards so that they could practice drawing these graphs. This proved to be very successful with students for the following reasons:

  • the novelty of using whiteboards
  • if they made a mistake this could be easily rubbed out and they could start again
  • it allowed me to go around the class to correct graphs where necessary
  • students took pride in their graphs
  • the best set of graphs was posted on the econfix blog
  • students who were struggling could learn off others

Foreign Aid – where does it come from?

Below is an informative clip from The Economist on foreign aid. Useful for A2 students looking at developing economies and foreign aid.

Rich countries are giving away more in aid than at any other time on record. In 2016 more than $140bn was distributed around the world. According to the latest breakdown in 2015 America gave the most money away – nearly $31bn to at least 40 countries and organisations such as the world bank. This included $770m to Pakistan and $250m to Mexico. This may sound generous but the United States has the largest economy in the world. American foreign aid spending in 2015 was only 0.17% of the gross national income. Far less than other rich countries. Sweden and Norway are the biggest givers, donating over 1% of their gross national income to foreign aid. The biggest receivers of aid in 2015 were Afghanistan, India, Vietnam, Ethiopia and Indonesia. Afghanistan received $3.8bn and India $3.1bn. Despite being the second biggest economy in the world, China received $1.5bn in development aid in 2015. This included around $750m from Germany and $67m from Britain. The total amount of foreign aid is at an all time high – up 9% in 2016. This is largely down to the generosity of six countries who meet or exceed the United Nations foreign aid target, donating more than 0.7% of gross national income.