IBDP Economics 2.5 Elasticity of demand HL Paper 1 - New Syllabus
Question
(a) Explain why the price elasticity of demand (PED) for primary commodities is generally lower than the PED for manufactured products. [10]
(b) Using real-world examples, discuss the importance of PED for the decision-making of firms and government. [15]
Most-appropriate topic code (CED):
▶️ Answer/Explanation
(a) Answer:
Price elasticity of demand (PED) measures the responsiveness of quantity demanded to a change in the price of a good, ceteris paribus. Primary commodities generally have a relatively inelastic demand, whereas manufactured products tend to have a relatively more elastic demand.
1. Primary commodities generally have fewer and less close substitutes.
Primary commodities such as crude oil, wheat and coffee are often important inputs into production or are basic necessities. In the short run, consumers and firms may have limited alternatives when their prices change. For example, a firm that requires a particular agricultural commodity as an input may find it difficult to replace it immediately with another commodity.
Therefore, even if the price of a primary commodity increases, the quantity demanded may fall by a relatively small percentage. This gives the commodity a relatively low PED, meaning that demand is relatively price inelastic.
In contrast, manufactured products such as clothing, smartphones and household appliances often have a greater number of close substitutes. If the price of one manufactured product increases, consumers can switch to competing brands or alternative products. As a result, quantity demanded may fall by a relatively large percentage, giving manufactured products a relatively higher PED.
2. Primary commodities are often necessities, while manufactured products may be more discretionary.
Many primary commodities are essential either directly for consumption or indirectly as inputs into production. Consumers and firms therefore find it difficult to reduce their consumption substantially following a price increase. This makes demand relatively inelastic.
Manufactured products are more likely to include discretionary goods for which purchases can be postponed or avoided. For example, if the price of a new television increases substantially, consumers may delay purchasing one or choose a cheaper alternative. Therefore, the quantity demanded may respond more strongly to a price change, making demand relatively elastic.
The proportion of income spent on a good can also influence PED. A primary commodity that represents a relatively small proportion of a consumer’s income may have less impact on purchasing decisions when its price changes. In contrast, expensive manufactured products can represent a larger proportion of income, making consumers more responsive to price changes.
The demand curve for a primary commodity would generally be relatively steep, showing an inelastic response to a change in price. The demand curve for a manufactured product would generally be relatively flatter, showing a more elastic response.
Therefore, the generally lower PED of primary commodities can be explained by their limited number of close substitutes, their importance as necessities or production inputs and, in many cases, their relatively small share of consumers’ expenditure. Manufactured products generally have more substitutes and are easier to postpone or replace, resulting in a relatively higher PED.
(b) Answer:
PED is important to the decision-making of both firms and governments because it indicates how strongly quantity demanded is likely to respond to a change in price. However, the usefulness of PED depends on how accurately it can be estimated and on the wider objectives of the decision-maker.
Importance for firms: pricing decisions and total revenue
If demand is price inelastic, an increase in price causes a proportionately smaller decrease in quantity demanded. Therefore, total revenue is likely to increase. This is important for firms considering whether to raise their prices.
For example, a pharmaceutical firm selling an essential medicine may face relatively inelastic demand because consumers have limited substitutes and may need the medicine regardless of its price. The firm may therefore have greater scope to increase its price without experiencing a proportionately large fall in sales revenue.
Conversely, when demand is price elastic, a price increase causes a proportionately larger fall in quantity demanded, so total revenue is likely to decrease. A firm facing highly elastic demand may therefore reduce its price to increase sales and potentially increase total revenue.
For example, a manufacturer selling a product in a highly competitive market may face many close substitutes. If it increases its price, consumers can easily switch to rival products. Understanding PED is therefore important when firms make pricing, sales and revenue decisions.
Importance for government: indirect taxation
PED is particularly important when governments impose indirect taxes. Governments may tax goods such as cigarettes and alcohol to generate revenue and reduce consumption of demerit goods.
If demand is relatively price inelastic, an increase in the tax-induced price causes a relatively small decrease in quantity demanded. The government can therefore raise significant tax revenue. At the same time, the higher price provides some incentive for consumers to reduce consumption.
For example, governments impose substantial excise taxes on tobacco products. Because demand for cigarettes can be relatively inelastic, especially in the short run due to addiction, governments can generate considerable tax revenue from tobacco taxation while also attempting to discourage consumption.
However, if demand is relatively price elastic, a higher tax can cause a large reduction in quantity demanded. This may be useful if the government’s main objective is to reduce consumption, but it may limit the additional tax revenue generated.
Importance for government: subsidies and resource allocation
PED can also influence decisions about subsidies. If the government wants to encourage consumption of a good, such as public transport or healthcare, it can provide a subsidy that lowers the price. The increase in quantity demanded will depend partly on the PED of the good.
For example, a subsidy that lowers public transport fares may increase passenger numbers. If demand is sufficiently price elastic, the fall in fares may lead to a substantial increase in quantity demanded, potentially reducing private car use and the negative externalities associated with congestion and pollution.
Thus, understanding PED helps governments predict whether an intervention is likely to significantly change consumption and improve resource allocation.
However, PED is difficult to measure accurately.
Firms and governments rarely know the exact PED of a product. Estimates are normally based on historical data, surveys or changes observed in markets. In reality, the ceteris paribus assumption is difficult to maintain because other factors such as income, consumer confidence, tastes, expectations and the prices of substitutes may change at the same time as the price of the good.
For example, if a firm raises the price of a product and sales subsequently fall, it may be difficult to determine how much of the fall was caused by the price increase and how much was caused by the introduction of a competing product or a fall in consumer income. This reduces the reliability of PED estimates.
Firms may also have objectives other than maximizing revenue.
A firm may aim to maximize profit, increase market share, maintain customer loyalty, improve its brand image or meet corporate social responsibility objectives. Therefore, even if PED suggests that a price increase would raise total revenue, the firm may choose not to increase its price if doing so could damage its reputation or cause consumers to switch to competitors in the long run.
Governments also have multiple objectives.
A government may impose an indirect tax for reasons other than maximizing tax revenue. It may aim to reduce consumption of a demerit good, correct a negative externality, improve public health or achieve an equity objective. Therefore, a tax on a product with highly inelastic demand may generate substantial revenue but may be considered unsuccessful if the government’s main objective was to reduce consumption significantly.
Overall evaluation: PED is highly important for firms because it helps them anticipate how price changes will affect quantity demanded and therefore total revenue. It is also important for governments when determining indirect taxes, subsidies and policies designed to influence consumption and resource allocation.
However, PED should not be treated as a precise measure because it is difficult to estimate accurately and other variables are rarely constant in the real world. In addition, firms and governments have objectives beyond revenue maximization, so the decision cannot be based on PED alone.
Therefore, PED is an important input into decision-making rather than a complete decision-making rule. Its importance is greatest when firms are making pricing decisions or governments are designing taxes and subsidies, but the final decision should also consider market conditions, wider economic and social objectives, the reliability of PED estimates and the likely long-run consequences.
Question
(a) Explain the importance of income elasticity of demand (YED) for the primary, manufacturing and service sectors of the economy when real incomes are rising. [10]
(b) Using real-world examples, evaluate the view that the consumption of demerit goods is best reduced through legislation and regulation. [15]
Most-appropriate topic code (CED):
• TOPIC 2.7: Role of government in microeconomics
▶️ Answer/Explanation
(a) Answer:
Income elasticity of demand (YED) measures the responsiveness of quantity demanded of a good or service to a change in consumers’ income, ceteris paribus. When real incomes rise, YED is important because it determines how quickly demand for different goods and services increases.
Primary sector: Primary commodities such as agricultural products and basic raw materials generally have a relatively low positive YED. As real incomes rise, consumers may increase their consumption of basic necessities such as food, but the increase in quantity demanded is proportionately smaller than the increase in income.
Consequently, as an economy becomes wealthier, demand for primary commodities tends to grow relatively slowly. This means that the relative importance of the primary sector may decline as a share of total economic activity, even though the absolute demand for some primary products may continue to increase.
Manufacturing sector: Manufactured products generally have a higher YED than basic primary commodities. As real incomes rise, consumers tend to purchase more manufactured goods such as cars, electronics, appliances and other durable goods. Therefore, demand for manufactured products can increase more rapidly than demand for basic commodities.
This can encourage firms in the manufacturing sector to expand production and investment as household incomes rise. As a result, the manufacturing sector may initially become increasingly important in the process of economic development.
Service sector: Many services have relatively high positive YED. As real incomes rise, consumers can devote a greater proportion of their income to services such as tourism, entertainment, financial services, education and healthcare. Demand for these services may therefore increase faster than income.
As a result, rising real incomes can cause the service sector to expand significantly and become a larger proportion of total economic activity. This helps explain the increasing importance of the tertiary sector in higher-income economies.
Inferior goods: Some goods and services have a negative YED. These are known as inferior goods. As real incomes rise, consumers demand less of them because they can afford to switch to higher-quality alternatives. For example, consumers may reduce their consumption of low-cost staple foods or basic forms of transport as their incomes increase.
An Engel curve can show the relationship between income and quantity demanded. For a normal good with positive YED, quantity demanded increases as income rises. For an income-elastic good, quantity demanded rises more than proportionately, while for an income-inelastic good it rises less than proportionately. For an inferior good, quantity demanded falls as income rises.
Therefore, YED is important for understanding the changing composition of an economy as real incomes rise. Low-YED primary commodities tend to experience slower growth in demand, while manufacturing and particularly many services can experience faster growth. Negative-YED inferior goods may experience falling demand as incomes increase.
(b) Answer:
A demerit good is a good whose consumption is considered harmful to consumers and may be overconsumed because individuals do not fully recognize the costs of consumption. Consumption may also impose negative externalities on third parties. Legislation and regulation involve government rules that directly restrict or control the consumption, production or availability of such goods.
Legislation and regulation can be effective because they directly restrict harmful consumption. Governments can prohibit certain forms of consumption, restrict where a product can be used, impose minimum age requirements or regulate its sale and advertising.
For example, smoking bans in public places directly restrict where cigarettes can be consumed. This reduces exposure of non-smokers to second-hand smoke and can also discourage smoking by making consumption less convenient. Similarly, restrictions on tobacco advertising reduce firms’ ability to encourage consumption.
Legislation can therefore directly reduce consumption and help move the marginal private benefit (MPB) of consumption closer to the marginal social benefit (MSB) by preventing or discouraging consumption that creates external costs.
Regulation can also be relatively easy to understand and enforce. A legal restriction establishes a clear rule that consumers and producers must follow. For example, governments can prohibit the sale of cigarettes to people below a specified age. This directly prevents a particular group from purchasing the product rather than relying entirely on consumers to change their behaviour voluntarily.
However, legislation and regulation are not necessarily the best policy in every situation.
One limitation is enforcement. If restrictions are too severe, consumers may attempt to avoid them through illegal markets or other forms of non-compliance. This can reduce the effectiveness of the policy and create additional costs for enforcement.
For example, severe restrictions on tobacco or alcohol may encourage some consumers to purchase products through informal or illegal channels. The government may then lose tax revenue while consumption continues.
Indirect taxation can be an alternative. An indirect tax raises the price of a demerit good, reducing quantity demanded and internalizing some of the external cost. The policy also generates government revenue, which can be used to fund healthcare or information campaigns.
For example, higher taxes on cigarettes increase the price of smoking and provide a financial incentive to reduce consumption. However, if demand is highly price inelastic because of addiction, the reduction in consumption may be relatively small even though tax revenue increases substantially.
Education and awareness campaigns provide another alternative. Governments can inform consumers about the health and social costs of consuming demerit goods. If consumers have imperfect information, providing accurate information may cause them to make better-informed decisions and reduce consumption voluntarily.
For example, public health campaigns explaining the health risks of smoking can discourage people from starting to smoke and encourage existing smokers to quit. However, information campaigns may be less effective where consumers already understand the risks but continue consuming because of addiction or other behavioural factors.
Nudges may also influence behaviour without directly prohibiting consumption. For example, governments can make healthier options more visible or change the way information is presented to consumers. Such policies preserve consumer choice but may produce a smaller effect than direct regulation.
Governments can also subsidize less harmful substitutes. For example, subsidizing public transport could make it cheaper relative to private car use. This may reduce consumption of private transport and associated negative externalities such as congestion and pollution, while maintaining consumer choice.
Real-world example: The regulation of tobacco provides evidence for the effectiveness of legislation. Restrictions on smoking in enclosed public places, advertising bans and minimum-age rules have reduced opportunities to consume and promote tobacco. However, tobacco taxation and public health campaigns have also played important roles, suggesting that regulation does not necessarily work best in isolation.
Another consideration is the nature of the demerit good. Direct regulation may be particularly effective when consumption creates substantial negative externalities or when consumption must be prevented in specific circumstances. For example, banning smoking in enclosed public places can directly protect third parties from second-hand smoke.
In contrast, where the objective is to reduce overall consumption while preserving consumer choice, an indirect tax may be more appropriate. The relative effectiveness therefore depends on the specific characteristics of the good and the government’s objective.
Overall evaluation: Legislation and regulation can be highly effective because they directly restrict harmful behaviour and can reduce negative externalities, particularly where consumption imposes significant costs on third parties. They are especially useful when the government needs a clear and immediate restriction.
However, the word “best” means that legislation and regulation must be compared with alternative policies. Indirect taxes can provide incentives to reduce consumption while generating government revenue; education can address information failure; nudges can influence behaviour while preserving choice; and subsidies for less harmful substitutes can encourage consumers to switch.
Therefore, legislation and regulation are not always the best method of reducing demerit-good consumption. They are likely to be most effective when direct control is necessary to prevent substantial harm to consumers or third parties. However, a combination of regulation, taxation, education and incentives may achieve a greater reduction in consumption while minimizing unintended consequences and preserving an appropriate degree of consumer choice.