Learning objectives
Explain the fundamental economic problem and the basic questions of what, how and for whom to produce
Define opportunity cost and apply it to individuals, firms and governments
Distinguish economic goods from free goods
Explain why economics is a social science, distinguish positive from normative statements, and explain ceteris paribus and the short run, long run and very long run
Identify the four factors of production and their rewards, distinguish human from physical capital, and explain the role of the entrepreneur
Key definitions
Scarcity
The situation in which wants are unlimited but the resources available to satisfy them are limited.
Opportunity cost
The benefit of the next best alternative forgone when a choice is made.
Economic good
A good that is scarce and therefore has an opportunity cost.
Free good
A good that is not scarce — it has zero opportunity cost, such as sunlight.
Normative statement
A statement based on a value judgement that cannot be tested against evidence.
Ceteris paribus
“Other things being equal”: the assumption that only the variable being studied changes while every other influence is held constant.
Human capital
The knowledge, skills, health and experience of workers that make them productive; physical capital is man-made equipment such as machines, vehicles and buildings.
Explanation
Every economy, household and firm faces the same problem: wants exceed the resources available to meet them. Because resources are scarce, every choice to use them one way forgoes another use. Economics is the study of how those choices are made and how they could be made better.
The basic questions. Because resources are scarce, every economy must decide what to produce (which goods and services, and how much of each), how to produce them (which combination of land, labour, capital and enterprise, and which technology) and for whom (how the output is shared out between people). Markets, governments or a mixture of the two answer these questions, as the topic on economic systems explains.
Opportunity cost is the sharpest tool in the subject. A student who spends an evening revising forgoes an evening's wages; a government that builds a hospital forgoes a road; a firm that invests retained profit in machinery forgoes the interest it could have earned. Rational decision-makers compare the benefit of a choice with its opportunity cost, not with its money price.
Economics as a social science. Economics studies human behaviour: how households, firms and governments respond to incentives when they make choices. Like a natural science it builds theories and tests them against evidence, but it can rarely run controlled experiments, because people and whole economies cannot be held still in a laboratory. Economists therefore build models that simplify reality, and the assumption of ceteris paribus (other things being equal) lets them isolate the effect of one change, such as a rise in price on the quantity demanded, while every other influence is held constant. Time matters too. In the short run at least one factor of production, usually capital, is fixed; in the long run all factors can be varied but the state of technology is given; in the very long run technology itself changes, together with the social, political and legal environment.
The four factors of production — land, labour, capital and enterprise — earn rent, wages, interest and profit respectively. Positive statements ("a rise in the minimum wage reduced youth employment by 2%") can be tested; normative statements ("the minimum wage should be higher") contain a value judgement. Examiners reward students who separate the two in evaluation.
Capital and enterprise. Physical capital is man-made equipment used to produce other goods, such as machines, vehicles and buildings; human capital is the knowledge, skills and health that make workers productive, built up through education, training and experience. Investment can add to either. The entrepreneur is the factor that organises the others: spotting an opportunity, deciding what to produce and how, raising finance, combining land, labour and capital, and bearing the risk that the venture makes a loss. Profit is the reward for taking that risk, which is why enterprise is treated as a factor separate from labour.
Worked examples
q: A farmer can grow either 40 tonnes of wheat or 100 tonnes of potatoes on her land. She chooses wheat. What is the opportunity cost of one tonne of wheat?
steps: Opportunity cost is measured in the alternative forgone: 100 tonnes of potatoes.
Per tonne of wheat: 100 ÷ 40 = 2.5 tonnes of potatoes.
Interpretation: each tonne of wheat costs the farmer 2.5 tonnes of potatoes she could have grown instead.
In context
A city that hosts a major sporting event forgoes the alternative uses of the stadium budget — schools, transport, debt repayment — which is why economists ask about opportunity cost rather than headline cost.
Air is a free good, but clean air in a polluted city is an economic good: people pay for purifiers and filters.
Common misconceptions
Treating opportunity cost as the money spent. It is the next best alternative, which may not be a monetary sum.
Calling all "good things" economic goods. The test is scarcity, not usefulness.
Confusing capital with money. In economics capital is a factor of production: physical capital is equipment and buildings, and human capital is skills; money is only a means of buying them.
Study tips
When asked for an example, name the alternative explicitly: "the opportunity cost of the new airport is the schools that could have been built with the same funds."
Positive vs normative is a favourite one-mark question — look for "should", "ought" and "fair" as normative signals.
For time periods, use the fixed factor as the test: something fixed → short run; all factors variable → long run; technology changing → very long run.
Evaluate the idea
Opportunity cost depends on the individual's alternatives, so the same choice has different costs for different people.
Some resources have no alternative use in the short run, making opportunity cost near zero.
Reasoning
Scarcity → choices must be made → every choice has an opportunity cost → resources should go to their highest-valued use → the price mechanism (or a planner) allocates them → efficiency depends on how well opportunity costs are signalled.
Summary
Scarcity forces choice about what, how and for whom to produce; choice creates opportunity cost.
Opportunity cost = next best alternative forgone.
Economic goods are scarce; free goods are not.
Positive statements are testable; normative statements are value judgements; ceteris paribus holds other things equal.
Physical capital is equipment, human capital is skills; the entrepreneur organises production and bears risk.
Check your understanding
Question 1: Which is a normative statement?
1. Inflation rose to 4% last year
2. The government should cut income tax
3. Unemployment fell after the training scheme
Question 2: The opportunity cost of attending university full-time is best described as…
1. the earnings and experience forgone from the best alternative
2. the cost of textbooks
3. the tuition fees
Question 3: In the very long run…
1. all factors of production are fixed
2. technology and the institutional environment can change
3. only labour can be varied