Demand

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The Relationship Between Price and Quantity Demanded

The demand curve illustrates the relationship between quantity demanded and price.

Price and quantity demanded

Price is what the buyer pays for a specific good or service.
Quantity demanded is the total number of units purchased at that price.
The demand curve is downward sloping and shows the relationship between price and quantity.
- This means that the higher the price is, the lower demand is.
The law of demand shows the inverse relationship between price and quantity, assuming all other variables are constant.

Willingness and ability to pay

Willingness to pay - desire to pay based on tastes and preferences.
Ability to pay - factors in a person's income, and whether they can afford the good or service or not.

Substitutes and complements

Substitute goods - an increase in the price of one good will increase the quantity demanded of the other good.
- E.g Persil and Ariel washing pods.
Complement goods - an increase in the price of one good will cause a decrease in the quantity demanded of the other good.
E.g flights to Spain and suncream.

Income and substitution effects

Two theories that explain the relationship between price and quantity are:
- Income effect - when prices fall, consumers can afford a greater quantity of goods and services (assuming income is fixed). So demand for these goods and services increases.
- Substitution effect - when the price of one good falls, consumers will buy more of the cheaper good or service and less of the more costly good or service. So demand for the cheaper good will increase; demand for the costlier good decreases.

Shifts in the Demand Curve

There are a number of factors that can cause the demand curve to shift.

Change in demand

The demand curve will shift right when there is an increase in demand for the good at each price level.
- E.g if a product were to suddenly become more popular, the demand curve would shift right.
The demand curve will shift left when there is a decrease in demand for the good at each price level.

Change in income

The effect of a change in income depends on the type of good.
For a normal good, increased income will lead to an increase in quantity demanded.
- E.g new cars.
For an inferior good, increased income may lead to a reduction in quantity demanded.
- E.g rice (if more expensive products like meat can be afforded).

Changes in prices cause a move along the curve

Movements along the curve happen in response to a price change.
- A rise in price will lead to a demand contraction.
- A fall in price will lead to a demand expansion.

Diminishing Marginal Returns

Diminishing marginal returns is the concept that the more of something you add, the lower the impact of each additional unit, assuming all else is fixed.

The law of diminishing marginal utility

Marginal utility is the extra benefit to an individual of consuming a good or service.
The law of diminishing marginal utility states that the more an individual consumes (ceteris paribus) the utility of the good/service decreases with every additional unit consumed.

Example of diminishing marginal utility

Diminishing marginal utility.
The first slice of Domino's pizza is very satisfying, but the 100th may not be quite as enjoyable.
Your tastes can be satiated (you can have enough of something). Eventually, the marginal utility of another slice of pizza may be negative.

The demand curve

The law of diminishing marginal returns can explain why the demand curve slopes downwards. As the quantity purchased rises, the price that consumers are willing to pay falls.
Consumers may be willing to pay a lower price for a higher volume because they gain less utility (or satisfaction) from each extra unit.

1Introduction to Markets

2Market Failure

2.1Market Failure

2.1.1Types of Market Failure

2.1.2Externalities

2.1.3The Deadweight Welfare Loss of Externalities

2.1.4A-A* (AO3/4) - The Externalities of Education

2.1.5Public Goods

2.1.6Information Gaps

2.1.7End of Topic Test - Market Failure

2.1.8Application Questions - Market Failure

2.2Government Intervention

2.2.1Government Intervention in Markets

2.2.2Subsidies & Price Controls

2.2.3Pollution Permits & Regulation

2.2.4A-A* (AO3/4) - European Emissions Trading

2.2.5State Provision & Information Provision

2.2.6Government Failure

2.2.7End of Topic Test - Government Intervention

2.2.8A-A* (AO3/4) - Government Intervention

3The UK Macroeconomy

3.1Measures of Economic Performance

3.1.1Measuring Economic Growth

3.1.2National Income Data

3.1.3Inflation

3.1.4Causes of Inflation

3.1.5Consequences of Inflation

3.1.6Employment & Unemployment

3.1.7Causes & Impact of Unemployment

3.1.8A-A* (AO3/4) - Hysteresis

3.1.9Balance of Payments

3.1.10Current Account Deficit & Imbalances

3.1.11End of Topic Test - Economic Performance

3.1.12Application Questions Macroeconomy

3.2Aggregate Demand

3.2.1Aggregate Demand

3.2.2Consumption

3.2.3Investment

3.2.4Government Expenditure

3.2.5Net Trade

3.2.6End of Topic Test - Aggregated Demand

3.2.7Application Questions - AD

3.3Aggregate Supply

3.3.1Aggregate Supply

3.3.2End of Topic Test - Aggregated Supply

3.3.3A-A* (AO3/4) -Aggregate Supply

3.4National Income

3.4.1National Income

3.4.2Injections & Withdrawals

3.4.3Equilibrium Level of Real National Output

3.4.4Multiplier Effect

3.4.5End of Topic Test - National Income

3.4.6Application Questions - National Income

3.5Economic Growth

3.5.1Causes of Economic Growth

3.5.2Output Gaps

3.5.3Business Cycle

3.5.4Impact of Economic Growth

3.5.5End of Topic Test - Economic Growth

3.5.6A-A* (AO3/4) - Growth

4The UK Economy - Policies

4.1Macroeconomic Objectives & Policies

4.1.1Possible Objectives

4.1.2Demand-Side Policies - Monetary

4.1.3Demand-Side Policies - Monetary 2

4.1.4A-A* (AO3/4) - The Future of Interest Rates

4.1.5Demand-Side Policies - Fiscal

4.1.6Demand-Side Policies in 2007-08

4.1.7Strengths & Weaknesses of Demand Side

4.1.8Supply-Side Policies

4.1.9Supply-Side Policies 2

4.1.10Conflicts Between Objectives

4.1.11A-A* (AO3/4) - Conflicting Incentives

4.1.12Phillips Curve

4.1.13End of Topic Topic - Policies & Objectives

4.1.14Application Questions - UK Policies

5Business Behaviour

5.1Business Growth

5.1.1Size & Types of Firms

5.1.2Business Growth

5.1.3Pros & Cons of External Expansion

5.1.4Demergers

5.1.5End of Topic Test - Business Growth

5.1.6A-A* (AO3/4) - Business Growth

5.2Business Objectives

5.2.1Business Objectives

5.2.2End of Topic Test - Business Objectives

5.2.3Application Questions - Business Objectives

5.3Revenues, Costs & Profits

5.3.1Revenue

5.3.2Costs

5.3.3Economies & Diseconomies of Scale

5.3.4Profits

5.3.5Profits 2

5.3.6End of Topic Test - Revenue, Costs & Profits

5.3.7A-A* (AO3/4) - Revenue, Costs & Profit

6Market Structures

6.1Market Structures

6.1.1Efficiency

6.1.2Perfect Competition

6.1.3Perfect Competition 2

6.1.4Monopolistic Competition

6.1.5Oligopolies

6.1.6The Prisoner's Dilemma

6.1.7Collusion in Oligopolistic Markets

6.1.8A-A* (AO3/4) - Which Factors Affect Collusion?

6.1.9Monopolies

6.1.10Price Discrimination

6.1.11Monopsony

6.1.12A-A* (AO3/4) - Models in Economics

6.1.13Contestability

6.1.14Benefits of Contestability

6.1.15End of Topic Test - Market Structures

6.1.16Application Questions - Market Structures

6.1.17A-A* (AO3/4) - Cereal Collusion

6.2Labour Market

6.2.1Demand for Labour

6.2.2Supply of Labour

6.2.3Labour Market Imperfections

6.2.4A-A* (AO3/4) - Labour Productivity & Unemployment

6.2.5A-A* (AO3/4) - What Level of Unionisation is Good?

6.2.6Wage Determination

6.2.7Elasticity of Labour Supply & Demand

6.2.8Intervention in Setting Wages

6.2.9End of Topic Test - Labour Market

6.2.10A-A* (AO3/4) - Labour Markets

6.3Government Intervention

6.3.1Reasons for Government Intervention

6.3.2Government Promotion of Competition

6.3.3Usefulness of Competition Policy & Examples

6.3.4A-A* (AO3/4) - Modern Competition Policy

6.3.5Privatisation

6.3.6Government Regulation

6.3.7A-A* (AO3/4) - Nationalisation vs Privatisation

6.3.8Government Protection of Suppliers and Employees

6.3.9Impact of Government Intervention

6.3.10End of Topic Test - Government Intervention

6.3.11Application Questions - Government Intervention

7A Global Perspective

8Finance & Inequality

8.1Poverty & Inequality

8.1.1Absolute & Relative Poverty

8.1.2Inequality

8.1.3Inequality 2

8.1.4Lorenz Curve

8.1.5Government Policy on Poverty

8.1.6End of Topic Test - Poverty & Inequality

8.1.7A-A* (AO3/4) - Inequality & Poverty

8.2Emerging & Developing Economies

8.2.1Measures of Development

8.2.2Factors Influencing Growth & Development

8.2.3Barriers to Development

8.2.4Barriers to Development 2

8.2.5A-A* (AO3/4) - The Bottom Billion

8.2.6Development Strategies

8.2.7Interventionist Strategies

8.2.8Aid

8.2.9International Institutions

8.2.10International Institutions 2

8.2.11End of Topic Test - Emerging & Developing

8.2.12Application Questions - Developing Countries

8.3The Financial Sector

8.3.1Role of Financial Markets

8.3.2Market Failure in the Financial Sector

8.3.3Role of Central Banks

8.3.4End of Topic Test - The Financial Sector

8.3.5A-A* (AO3/4) - Financial Sector

8.4Role of the State in the Macroeconomy

8.4.1Public Expenditure

8.4.2Taxation

8.4.3Public Sector Finances

8.4.4End of Topic Test - Role of the State

8.4.5Application Questions - Role of the State

9Examples of Global Policy

9.1International Policies

9.1.1Global Debt & Deficit Policies

9.1.2Poverty & Inequality Policies

9.1.3Changes in Interest Rates

9.1.4Competitiveness Policies

9.1.5End of Topic Test - International Policies

9.1.6A-A* (AO3/4) - International Policies

9.2Policy Responses to Shocks

9.2.1International Tax Policies

9.2.2Problems for Policymakers

9.2.3End of Topic Test - Policy Responses

9.2.4Application Questions - Policy Responses

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