The definition and function of markets

Markets act as platforms where buyers and sellers interact to exchange goods and services. They play a key role in determining how resources are allocated in an economy.

How prices and quantities are determined in markets

The price and quantity of goods or services traded depend on the balance between demand from buyers and supply from sellers. Diagrams are commonly used to illustrate these relationships, showing how price levels connect with the amounts demanded or supplied.

Understanding demand and demand curves

Demand refers to the amount of a good or service that buyers are both willing and able to purchase at a specific price during a given period.

Key features of demand curves

A demand curve illustrates the link between the price of a good or service and the quantity that consumers demand. It typically slopes downwards, indicating that as prices fall, more buyers can afford the item, leading to higher quantities demanded. This pattern reflects consumers' preference for lower prices and follows the law of diminishing marginal utility.

Movements along and shifts in demand curves

Changes in price cause movements along the demand curve, while other factors lead to shifts of the entire curve.

Movements along the demand curve

• Extensions in demand - A price drop encourages more purchases, increasing quantity demanded (e.g., from Q₁ to Q₂ as price falls from P₁ to P₂).
• Contractions in demand - A price rise reduces purchases, decreasing quantity demanded (e.g., from Q₂ to Q₁ as price rises from P₂ to P₁).

These changes occur solely due to price variations, with the curve itself staying in place.

Shifts in the demand curve

• Rightward shift - Indicates increased demand at every price level.
• Leftward shift - Shows decreased demand at every price level.

Shifts reflect broader changes in consumer behaviour or economic conditions, not just price.

Factors influencing shifts in demand

Several elements can alter overall demand, causing the demand curve to shift left or right. These include consumer trends, income levels, and income distribution.

Changes in tastes and fashions

Shifts occur when preferences evolve; for example, a surge in popularity for eco-friendly products can move the demand curve rightward, while declining interest in outdated items shifts it leftward.

Changes in real income

Real income measures what consumers can actually buy with their earnings after accounting for inflation.

• Normal goods - Items like branded electronics see demand rise (rightward shift) with increasing real income.
• Inferior goods - Products like budget own-brand items experience falling demand (leftward shift) as real income grows.

Distribution of income

A more even spread of income may cause the demand curve for luxury goods to shift to the left and the demand curve for other items to shift to the right.

The impact of interrelated markets on demand

Markets do not operate in isolation; changes in one can influence others through connections between goods.

Types of interrelated goods and their effects

• Substitute goods - Alternatives like butter and margarine. A price increase in one reduces its demand and boosts demand for the substitute (competitive demand).
• Complementary goods - Items used together, such as smartphones and chargers. A price rise in one decreases demand for both, shifting the complement's demand curve leftward (joint demand).
• Derived demand - Demand for inputs tied to another product's demand, e.g., rising need for cars increases demand for steel.
• Composite demand - Goods with multiple uses, like wheat for bread or animal feed. Increased demand in one use (e.g., baking) can limit availability for others, potentially raising prices and shifting supply curves in those markets.

Effects of new products on interrelated markets

Launching a new item can decrease demand (leftward shift) for its substitutes while increasing demand (rightward shift) for its complements, reshaping market dynamics.