Needs
Goods or services required for basic life and wellbeing, such as essential food, water and shelter.
Cambridge International AS Level Economics · 9708 · Chapter 1
Introducing economics
Economics begins with scarcity: resources are limited while human wants are extensive. This chapter builds the core way economists think about choice, opportunity cost, resource allocation, productive resources, economic systems, production possibility curves and different types of goods.
Book-aligned notesClear worked examplesExplained figures
What this chapter prepares you to do
You should be able to use economic terminology accurately, explain cause-and-effect relationships and apply the ideas to unfamiliar situations. The aim is not to memorise isolated definitions: high-mark answers connect a concept to a decision, consequence or diagram.
High-grade habit: define the concept, apply it to the context, then explain the economic consequence. For diagrams, label axes and curves clearly and describe what a movement or shift means.
Chapter sections
1.1
Scarcity, choice and opportunity cost
The fundamental economic problem
ScarcityThe condition in which available resources are limited relative to the wants people would like to satisfy.
Scarcity applies in every economy, including wealthy ones. It does not mean the same thing as poverty. Poverty concerns whether people can obtain basic necessities; scarcity exists because no society has enough resources to satisfy every possible want.
Wants
Desires for additional goods and services. Wants can expand as income, tastes and technology change.
Scarcity forces choice
Because resources have alternative uses, economic agents must choose. Households choose what to buy and how much labour to supply; firms choose what and how to produce; governments choose how to use tax revenue and public resources.
Limited resourcesLand, labour, capital and enterprise are finite
→ChoiceResources must be allocated between competing uses
→Opportunity costThe next-best alternative is sacrificed
Decision making at the margin
Marginal principleDecisions are often made by considering the effect of a small additional change from the current position.
A firm might produce one more unit only if the extra revenue justifies the extra cost. A consumer might buy one more item only if the additional benefit is worth the price. Much of later microeconomics develops this idea.
Microeconomics and macroeconomics
| Area | Focus | Examples |
|---|---|---|
| Microeconomics | Individual households, firms and particular markets. | The price of coffee; wages in construction; a firm's output decision. |
| Macroeconomics | Economy-wide variables and their relationships. | Inflation, national unemployment, total demand and economic growth. |
Opportunity cost
Opportunity costThe value of the next-best alternative that is given up when a choice is made.
The word next-best matters. If a government directs more resources towards healthcare, the opportunity cost is the most valuable alternative use of those resources that can no longer be undertaken. The concept applies to individuals, firms and governments.
Example: a student has time either to revise economics or work a paid shift. If the student revises, the lost earnings from the shift may be the opportunity cost.
The three basic questions of resource allocation
What?
Which goods and services should be produced, and in what quantities?
How?
Which production methods and combinations of resources should be used?
For whom?
How should the resulting goods and services be distributed among people?
Exam tip: when a question asks about opportunity cost, name the specific alternative forgone. Do not simply write “the cost of the choice”.
1.2
Economic methodology
Economics as a social science
The real economy is too complex to examine every influence at once. Economists therefore use simplified representations called models. Models help isolate important relationships, but their conclusions depend on the assumptions used.
Economic modelA simplified representation of reality used to analyse economic behaviour, relationships or events.
Economics is a social science because it studies human behaviour. Individuals are not perfectly predictable, so economists often analyse broad patterns and use assumptions such as consumers seeking satisfaction and firms seeking objectives such as profit.
Positive and normative statements
| Type | Meaning | Example |
|---|---|---|
| Positive | A claim about what is, or what may happen, that can in principle be tested against evidence. | “A higher cigarette tax is likely to reduce quantity demanded.” |
| Normative | A claim involving a value judgement about what ought to happen. | “The government should raise the cigarette tax.” |
Value judgementAn opinion based on beliefs or values rather than a statement that can be settled only by factual evidence.
Clue words: “should”, “ought”, “fair” and “better” often indicate a normative judgement, but always read the whole statement.
Ceteris paribus
Ceteris paribus“Other things being equal”: one influence is changed while other relevant influences are assumed to remain constant.
This assumption allows economists to focus on a single relationship before gradually adding more complexity. For example, when studying how price affects quantity demanded, other influences on demand may initially be held unchanged.
Why the time period matters
Responses can differ between the short run and longer periods. A consumer may need time to change habits. A firm may be able to increase workers' hours quickly but need much longer to build a factory or adopt a new technology. Therefore the effect of an economic change often depends on how much time has passed.
1.3
Factors of production
Production requires resources. Economists group these productive inputs into four broad factors.
Land
Natural resources used in production, including physical land and raw materials. Some are renewable; others, such as fossil fuels, are non-renewable.
Labour
Human effort used in production, including workers with different skills, training and experience.
Capital
Produced resources used to help make other goods and services, such as machinery, buildings, tools and equipment.
Enterprise
The entrepreneurial ability to organise resources, identify opportunities, innovate and bear risk.
Physical capital, fixed capital and working capital
Physical capital is different from money itself: it means produced assets used in production. Fixed capital lasts across many production cycles, such as machinery or factory buildings. Working capital refers to inputs used up during the production process, such as materials and components.
Do not confuse: human capital is the stock of skills and expertise that makes workers productive. A firm can own physical capital, but it cannot own its workers.
Rewards to factors of production
| Factor | Typical reward | Why it is paid |
|---|---|---|
| Land | Rent | Payment for the use of natural resources or land. |
| Labour | Wages / salaries | Payment for workers' time, effort and skills. |
| Capital | Interest | Return associated with using capital rather than placing funds in an alternative financial use. |
| Enterprise | Profit | Reward for organising resources and bearing business risk. |
Division of labour and specialisation
Division of labourBreaking production into separate stages so workers or firms specialise in particular tasks.
Specialisation can occur between workers, firms and countries. It can raise output because people become more skilled at repeated tasks, less time is lost switching activities, natural differences in ability are used more effectively, and large-scale production may become easier.
Adam Smith’s pin example: The book uses the classic division-of-labour example in which one worker completing every stage could make only about 20 pins a day. Ten workers working in the same unspecialised way would therefore make about 200. If production is split into specialised stages, the same ten workers could produce about 48,000 pins a day. The point is not the exact historical number; it is how practice, task specialisation and less time switching between jobs can raise productivity dramatically.
Advantages
- Higher worker productivity through practice.
- Better use of different skills and resources.
- Less time lost moving between tasks.
- Can support larger-scale, more efficient production.
Risks of overspecialisation
- Repetitive work may reduce motivation and concentration.
- Firms become vulnerable if demand for a narrow product range falls.
- Countries may become too dependent on imports or one export industry.
Labour productivityOutput produced per worker, or per unit of labour input, over a period.
Specialisation beyond individual workers: The book extends the idea to firms and countries. In car manufacturing, one firm may specialise in tyres, another in windscreens and another in final assembly. Countries also specialise where their resources are better suited: for example, the UK is not naturally suited to commercial pineapple or mango production, while it has developed specialist activity around Formula 1 teams.
The role of the entrepreneur
Entrepreneurs add dynamism to an economy by recognising possible income-earning opportunities, combining the other factors of production, innovating and accepting the risk that a project may fail. This role can be especially important in new and smaller firms.
Short run, long run and very long run
| Time period | Economic meaning | Illustration |
|---|---|---|
| Short run | At least one factor is fixed; a firm may be able to vary labour but not all other inputs. | Use overtime before new machinery can be installed. |
| Long run | All factors of production can be varied. | Expand premises and add machinery as well as labour. |
| Very long run | Technology and the wider policy environment may also change. | Adopt a new production technology or respond to major regulatory change. |
1.4
Resource allocation in different economic systems
An economic system coordinates millions of decisions about what, how and for whom to produce. The key difference between systems is the balance between market forces and state direction.
Market economy
Prices, consumer choices and profit incentives guide most resource allocation. Secure property rights and a stable framework help markets operate.
Centrally planned economy
The state directs production and resource allocation. Planning can pursue social priorities directly but requires huge amounts of information and administration.
Mixed economy
Markets allocate many resources, while government also taxes, spends, regulates and supplies or influences some activities.
How price signals coordinate a market economy
Consumer preferences changeBuying decisions alter demand
→Prices & profitability changeSignals and incentives are created
→Firms reallocate resourcesProduction responds to market conditions
Comparing systems
| Issue | Market-oriented system | Central planning |
|---|---|---|
| Coordination | Decentralised through prices and market decisions. | Decisions are coordinated by government plans. |
| Information | Prices transmit information about scarcity and preferences. | Planners must gather and process large volumes of information. |
| Incentives | Profit and private ownership can encourage innovation and responsiveness. | Targets may not always create the intended incentives. |
| Government role | Usually smaller, though still needed for rules, property rights and market failures. | Large role in deciding output and distribution. |
Why planning targets can create unintended incentives: The book gives a historical example from centrally planned Russia. Some nail factories were given targets based on the number of nails, encouraging very small nails; others were given targets based on weight, encouraging a few very large nails. Both groups could satisfy the target without producing the mix planners actually wanted. This illustrates the information and incentive problems that can arise under detailed central planning.
Mixed and transition economies
Most modern economies are mixed rather than purely market or purely planned. The degree of intervention differs between countries. Transition economies are economies moving from extensive central planning towards greater use of markets. The adjustment can be difficult because prices, firms, workers and institutions must adapt to new incentives, risk and decision-making freedom.
Evaluation point: avoid saying one system is simply “best”. The outcome depends on the objective being considered, the quality of institutions and the effectiveness of both markets and government intervention.
1.5
Production possibility curves (PPCs)
Production possibility curveA boundary showing the maximum attainable combinations of two goods or services that can be produced in a period using available resources and technology efficiently.
A PPC turns scarcity, choice and opportunity cost into a diagram. It assumes a fixed quantity and quality of resources and a given state of technology for the period shown.
Capital and consumer goods
Point A lies on the production possibility curve and represents a feasible, productively efficient combination of consumer and capital goods. Point B is outside the current PPC and is unattainable with existing resources and technology, while point C is inside the PPC and indicates that some resources are unemployed or underused.
Adapted from Cambridge International AS & A Level Economics, Second Edition, by Peter Smith (with Adam Wilby and Mila Zasheva).
A very simple PPC before the economy-wide version: The book first imagines Abdul with limited study time and five economics questions and five maths exercises. If each task takes the same time, doing one more economics question means giving up one maths exercise. This produces a straight PPC because the opportunity cost is constant. The same logic then scales up to an economy choosing between categories such as consumer and capital goods.
Economic growth
The outward movement from PPC₀ to PPC₁ shows an increase in productive capacity. With more or better factors of production, or improved technology, the economy can produce a greater quantity of both categories of output than before.
Adapted from Cambridge International AS & A Level Economics, Second Edition, by Peter Smith (with Adam Wilby and Mila Zasheva).
Opportunity cost and the shape of the PPC
Moving along a PPC means producing more of one output only by giving up some of the other. A straight PPC indicates constant opportunity cost. A bowed-out PPC usually reflects increasing opportunity cost because resources are not equally suited to both uses.
Easy book example: Suppose you have enough money for either a can of cola or a snack from a street vendor. If you choose the cola, the snack is the opportunity cost because it is the next-best alternative forgone. The same logic applies to government: if more scarce resources are devoted to healthcare, fewer are available for another use such as defence.
Opportunity cost and the production possibility curve
The farmer can increase sweet-potato output from 180 to 250 tonnes only by reducing onion output from 300 to 250 tonnes. The opportunity cost of the extra 70 tonnes of sweet potatoes is therefore 50 tonnes of onions.
Adapted from Cambridge International AS & A Level Economics, Second Edition, by Peter Smith (with Adam Wilby and Mila Zasheva).
Consumer goods, capital goods and growth
Consumer goods provide current consumption. Capital goods are used to increase or support future production. Choosing more capital goods today may require less current consumption, but it can increase future productive capacity.
Investment
Spending that adds to the capital stock and can increase future productive capacity.
Consumption
Household spending on goods and services for current use.
Shifts in the PPC
- Outward shift: more resources, better-quality resources or technological progress raise potential output.
- Inward shift: loss or destruction of productive resources reduces capacity.
- Biased shift: a technology improvement benefiting only one sector pivots or changes the shape of the PPC rather than shifting it equally everywhere.
Potential economic growthAn increase in an economy's productive capacity, represented by an outward movement of its PPC.
Diagram tip: a movement along a PPC shows a reallocation of existing resources. A shift of the PPC shows a change in productive capacity.
1.6
Classification of goods and services
Free goods and private (economic) goods
Free good
A good not normally regarded as scarce because availability exceeds the amount people want at a zero price in the relevant situation. Clean atmospheric air is a common example, although environmental change can make formerly abundant resources scarce.
Private / economic good
A scarce good. Private goods are normally excludable, rival in consumption and rejectable.
Three characteristics of a private good
Excludable
People who do not pay can generally be prevented from consuming it.
Rival
Consumption by one person reduces the amount available to others.
Rejectable
A person can choose not to consume it.
Public goods and the free-rider problem
Public goodA good that is non-excludable, non-rival and non-rejectable once provided.
Examples often include street lighting or a lighthouse. Because non-payers cannot easily be excluded, people can benefit without paying. This creates the free-rider problem, which weakens the incentive for private firms to provide a pure public good through the market.
Important distinction: a publicly provided service is not automatically a public good. State education and healthcare can be publicly funded, but they do not have all the characteristics of a pure public good.
Some goods are semi-public. A road may be non-excludable when no toll exists, but heavy congestion makes consumption rival because one driver's use reduces the quality available to others.
Merit and demerit goods
| Type | Why the market outcome may be inappropriate | Typical direction of consumption | Examples |
|---|---|---|---|
| Merit good | Consumers may underestimate or not fully understand the benefits. | Under-consumed in a free market. | Education; preventive healthcare. |
| Demerit good | Consumers may underestimate costs or overestimate benefits. | Over-consumed in a free market. | Tobacco; harmful drugs. |
The underlying issue is often information failure: consumers do not have, understand or act on complete information about the consequences of consumption. Identifying merit and demerit goods can also involve normative judgements about what society considers desirable.
Merit-good example: Education may be under-consumed if parents do not fully understand its long-term benefits. The book explains that the government may therefore intervene, for example by imposing a minimum school-leaving age. The justification is information failure: society believes the benefit of education is greater than some consumers perceive.
Chapter 1 revision checklist
Explain scarcity and why it creates choice.
Distinguish wants from needs and scarcity from poverty.
Apply the marginal principle to a decision.
Distinguish microeconomics from macroeconomics.
Define and apply opportunity cost.
Use the “what, how, for whom” framework.
Explain why economists use models.
Distinguish positive from normative statements.
Explain ceteris paribus and why time matters.
Identify all four factors of production and their rewards.
Distinguish fixed, working, physical and human capital.
Analyse advantages and risks of specialisation.
Explain the role of an entrepreneur.
Distinguish short, long and very long run.
Compare market, planned, mixed and transition economies.
Interpret points and movements on a PPC.
Explain constant and increasing opportunity cost.
Explain causes of outward, inward and biased PPC shifts.
Distinguish free, private, public, merit and demerit goods.
Explain the free-rider problem and information failure.
18 questions. Each answer is marked immediately with a short explanation of why it is correct or incorrect.