Factors Affecting Market Demand (HSC SSCE Economics): Revision Notes
Factors Affecting Market Demand
Understanding market demand
Demand is the quantity of a particular good or service that consumers are willing and able to purchase at various price levels at a given point in time. Both conditions—willingness and ability to pay—must be met for economists to recognise demand.
Market demand differs from individual demand. While individual demand refers to one consumer's demand for a good or service, market demand represents the total demand from all consumers in the market. Market demand is calculated by adding up the quantities demanded by all individual consumers at each price level.
The six main factors affecting market demand
Market demand is influenced by multiple factors. Understanding these helps explain why demand for goods and services changes over time.
1. The price of the good or service itself
When consumers consider purchasing a good, they must decide whether the price is acceptable. This decision depends partly on whether the good is a necessity or a luxury.
Understanding Necessities vs Luxury Items
The distinction between necessities and luxury items is crucial for understanding how price changes affect consumer behavior:
- Necessities are goods essential for daily life, with relatively stable demand even when prices change
- Luxury items are more sensitive to price changes, as consumers can more easily reduce demand for non-essential goods
Necessities are goods essential for daily life. Demand for these items remains relatively stable even when prices change. For example, if basic food prices rise, people will not significantly reduce their food purchases because they need it for survival. However, they may cut back on other goods instead.
Luxury items are more sensitive to price changes. When the prices of non-essential goods increase, consumers are more likely to reduce their demand for these products. Examples include designer clothing, expensive restaurants, and high-end electronics.
Worked Example: Price Sensitivity in Different Markets
Consider two scenarios:
Scenario 1 - Necessity (Bread):
- Initial price: $3.00 per loaf
- Price increases to: $3.50 per loaf
- Consumer response: Minimal reduction in quantity purchased (people still need bread)
- Demand remains relatively stable
Scenario 2 - Luxury (Restaurant Meals):
- Initial price: $50 per meal
- Price increases to: $65 per meal
- Consumer response: Significant reduction in quantity purchased (people can cook at home)
- Demand falls substantially
2. The price of other goods and services
Consumer demand for a good is also affected by the prices of related goods. These relationships fall into two categories:
Substitutes are goods that consumers can use in place of each other. Examples include:
- Butter and margarine
- Netflix and Foxtel Now subscriptions
- Different brands of mobile phones
When the price of one substitute rises, demand for the alternative substitute typically increases. For instance, if margarine prices increase, more consumers will switch to butter, causing butter demand to rise.
Worked Example: Substitute Goods
Consider the market for streaming services:
Initial situation:
- Netflix subscription: $15/month
- Foxtel Now subscription: $25/month
- Many consumers choose Netflix due to lower price
Price change:
- Netflix increases price to $20/month
- Foxtel Now price remains $25/month
Result:
- Some Netflix subscribers switch to Foxtel Now (or other alternatives like Disney+)
- Demand for Foxtel Now increases as consumers seek substitutes
- The price difference has narrowed, making alternatives more attractive
Complements are goods that consumers typically purchase together. Examples include:
- Blu-ray players and Blu-ray discs
- Cars and petrol
- Printers and ink cartridges
When the price of one complement increases, demand for both goods usually falls. If car prices rise, fewer people will buy cars, which also reduces demand for petrol.
Worked Example: Complementary Goods
Consider the relationship between printers and ink cartridges:
Scenario:
- A consumer purchases a printer for $200
- Printer requires specific ink cartridges at $80 per set
- Consumer needs to replace cartridges every 3 months
Price increase:
- Ink cartridge price rises to $120 per set
- Annual ink cost increases from $320 to $480
Result:
- Higher ongoing costs make printer ownership less attractive
- Demand for both printers and ink cartridges falls
- Some consumers switch to printing services instead
3. Expected future prices
Consumer behaviour is influenced not only by current prices but also by anticipated future price changes. When consumers expect a price increase in the near future, they often bring forward their purchases to avoid paying higher prices later. This increases current demand for the product.
Worked Example: The GST Introduction in Australia
A clear example occurred in Australia in 2000, when the government introduced the Goods and Services Tax (GST):
Situation:
- GST announced to take effect on 1 July 2000
- New tax would increase prices on many goods and services
- Consumers knew exact date when prices would rise
Consumer response:
- Significant surge in expenditure on home building in months before July
- Rush to complete purchases before prices increased
- Current demand increased substantially as purchases were brought forward
Result:
- Temporary spike in demand before GST implementation
- Followed by reduced demand after GST took effect
4. Changes in consumer tastes and preferences
As consumer preferences evolve, so does demand for particular goods. Several forces drive these changes:
Fashion trends significantly affect demand for clothing and accessories. Items that come into fashion experience increased demand, while those going out of fashion see demand decline.
The Impact of Technological Progress
Technological progress and innovation cause consumers to demand newer, improved products while abandoning older ones. The music industry illustrates this clearly: while CD sales once dominated the market, consumers now predominantly purchase music through digital downloads and streaming services accessed via smartphones and computers.
Innovation creates entirely new product categories and makes existing products obsolete, fundamentally reshaping demand patterns across industries.
5. The level of income
Income plays a crucial role in determining consumer demand through several mechanisms:
Income levels: As people earn higher incomes, they become more willing and able to purchase goods and services previously beyond their reach. Rising incomes tend to increase demand for luxury goods more than necessities, as essential items remain relatively insensitive to income changes.
Income Distribution and Consumer Expectations
Two additional income-related factors significantly affect demand:
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Income distribution refers to how an economy's income is spread among different social and socioeconomic groups. Changes in income distribution alter demand patterns for specific goods. For example, if income redistribution favours higher-income earners, demand for luxury goods will likely increase.
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Consumer expectations about future income and economic prospects influence purchasing decisions. If the economic outlook appears uncertain and consumers fear potential job losses, they become less likely to purchase expensive luxury items, even if they currently have sufficient income. This precautionary behaviour helps explain why demand can decline during economic uncertainty even before actual income falls.
6. The size of the population and its age distribution
Demographics affect market demand in two important ways:
Population size influences the total quantity of goods demanded. A larger population creates greater overall demand for most goods and services.
Age distribution affects the types of goods demanded. Different age groups have different needs and preferences.
Australia's Ageing Population
Australia's ageing population provides a clear example of how demographic changes influence market demand. As the proportion of older Australians increases, there has been a corresponding increase in demand for:
- Retirement villages
- Aged care services
- Healthcare products designed for older consumers
- Medical equipment and pharmaceuticals
Network externalities
Sometimes consumer behaviour is influenced by the purchasing decisions of others. When one person's demand is affected by how many other people have purchased a good, a network externality exists.
Worked Example: The Bandwagon Effect
The bandwagon effect (positive network externality) occurs when people demand a good precisely because many others own it. Consumers want to follow the crowd and not be left out.
Consider popular children's toys:
- A new toy becomes popular among children at school
- More children ask parents to buy the toy because "everyone has one"
- Demand increases simply because the product is popular
- Parents feel pressure to purchase to avoid their child feeling excluded
Other examples include:
- Fashionable clothing items spreading through social influence
- Widely-adopted technology platforms (e.g., social media apps)
- Trending consumer electronics
Worked Example: The Snob Effect
The snob effect (negative network externality) occurs when demand for a good is higher precisely because fewer people own it. Some consumers value exclusivity and uniqueness.
Consider limited-edition luxury watches:
- Manufacturer produces only 100 units worldwide
- High price point ($50,000+) excludes most consumers
- Scarcity and exclusivity make the watch more desirable
- Demand increases precisely because ownership is rare
Other examples include:
- Rare works of art with limited availability
- Limited-edition sports cars
- Exclusive designer items with restricted production
The ceteris paribus assumption
Economic analysis becomes complex when multiple factors change simultaneously. To simplify analysis, economists use the ceteris paribus assumption, a Latin phrase meaning "other things being equal" or "assuming nothing else changes."
Why Ceteris Paribus Matters
This assumption allows economists to isolate the relationship between two specific variables by holding all other factors constant. For example, when examining how price affects demand, we assume that income, preferences, prices of other goods, and all other demand factors remain unchanged.
This analytical tool helps us understand individual relationships clearly. Once we understand each factor's effect in isolation, we can then consider how multiple factors interact in real-world situations.
For instance, we might say: "If the price of a good falls, then ceteris paribus, sales will increase."
Key Points to Remember:
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Market demand is the total demand from all consumers, calculated by summing individual consumer demand at each price level.
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Six main factors affect market demand: the good's own price, prices of related goods (substitutes and complements), expected future prices, consumer tastes and preferences, income levels, and population characteristics.
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Substitutes can replace each other (when one's price rises, demand for the other increases), while complements are purchased together (when one's price rises, demand for both falls).
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Income effects are stronger for luxury goods than necessities. Income distribution and consumer expectations about future income also significantly influence demand.
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Network externalities show how other consumers' behaviour affects individual demand through the bandwagon effect (following the crowd) or snob effect (seeking exclusivity).
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The ceteris paribus assumption is essential for economic analysis, allowing economists to isolate and examine one factor's effect while holding all others constant.