1.3.1 - Introductory concepts

Economics is a social science because it studies how people, firms and governments make choices and interact. Their behaviour can respond to expectations, institutions and changing circumstances, so it is harder to isolate causes than in a controlled laboratory experiment.

An economist usually cannot hold an entire economy constant, randomly assign countries to policies, or repeat a recession under identical conditions. Such experiments may be impractical or unethical, and many relevant variables change at the same time. Much economic evidence is therefore observational or comes from limited natural and field experiments.

Economists still form hypotheses, compare predictions with data and revise explanations. However, a relationship observed in data may be correlation rather than causation, and a conclusion may be conditional or probabilistic rather than a universal law.

An economic model is a simplified representation of part of the economy. It selects the variables and relationships needed to answer a question, while assumptions temporarily set aside details that would obscure the mechanism.

A simple market model may assume many buyers and sellers and treat product quality as unchanged. It can then focus on how a change in price affects planned purchases. The model is useful if it clarifies the relationship, even though real markets contain more detail.

Ceteris paribus means 'other relevant things being equal'. It allows a model to isolate the predicted effect of one changed variable while holding other influences conceptually constant.

Suppose a model predicts that a higher price reduces quantity demanded. The conclusion is ceteris paribus: income, tastes, the prices of related goods and other demand conditions are assumed unchanged. If income rises at the same time, the observed quantity could rise despite the price increase, so the price effect cannot be identified from the total change alone.

State the changed variable, the outcome and the important factors being held constant. This makes the causal reasoning transparent and shows when new evidence would require the conclusion to be qualified.

Words such as 'should', 'fair' and 'better' often signal a normative judgement, but classification depends on meaning. A statement predicting what a policy will do is positive even if uncertain; a statement choosing the outcome society ought to prefer is normative.

Separate the two in an argument: first test the positive claim with relevant data, then identify the value judgement used to recommend or reject the policy.

A value judgement is a view about which outcomes deserve priority. Economic policy requires such judgements because decision makers must weigh objectives such as efficiency, equality, freedom, environmental protection and security.

Positive analysis may estimate who gains, who loses, how large an effect may be and what opportunity cost arises. The policy choice then depends partly on the weight placed on those consequences. Two decision makers can accept the same evidence yet prefer different policies because they value the outcomes differently.

Evidence might predict that a pollution tax reduces emissions but raises household energy costs. Supporting the tax may reflect a judgement that environmental benefits outweigh the cost; opposing it may place greater weight on affordability or distributional effects.

The basic economic problem is scarcity: human wants are unlimited relative to the finite resources available at a particular time. Labour, land, capital and enterprise cannot produce every desired good and service simultaneously.

Scarcity forces households, firms and governments to choose what to produce, how to produce it and who receives it. Using a resource for one purpose prevents its simultaneous use elsewhere, creating an opportunity cost.

A government with a fixed budget may want more hospitals, schools and transport. Funding all desired projects is impossible, so allocating more to one area means giving up the best alternative use of those funds.

The distinction affects long-run availability and production choices. Depleting a non-renewable stock leaves less for future use; investment in renewable capacity can reduce dependence on that stock.

Opportunity cost is the value of the next best alternative forgone when a choice is made. It exists because scarce resources cannot be used for every alternative at once.

Identify the choice, list the feasible alternatives, and find the most valuable alternative not selected. That next best option—not every option forgone—is the opportunity cost.

If a council uses a plot of land for a library rather than its best alternative, a health centre, the opportunity cost is the value of the health centre's benefits. The construction bill is a financial cost; it is not by itself the opportunity cost.

Classification depends on circumstances. Water may act as a free good where it is naturally abundant and accessible, but become an economic good during drought or where treatment and distribution use scarce resources.

A production possibility frontier (PPF) shows the maximum combinations of two outputs an economy can produce with its current resources, technology and efficiency.

A movement along the frontier reallocates resources. The marginal opportunity cost of one more unit of good $X$ is the amount of good $Y$ given up between the two production points.

An outward frontier represents economic growth or greater productive potential; an inward frontier represents economic decline. Label both output axes and state the resources/technology conditions when interpreting any point.

A larger or more productive labour force, better capital or improved technology raises potential output and shifts the frontier outward. The effect may be biased: innovation specific to one industry can rotate or shift one end farther than the other.

The cause matters. Education and capital investment often work after a time lag and may fail to raise capacity if skills or equipment are poorly matched. Population growth raises potential output only if additional workers can participate productively.

Classification depends on use rather than physical appearance. A computer used in a design business is a capital good; the same model used by a household for entertainment is a consumer good.

Producing more capital goods can reduce current consumer-goods output because resources are scarce, but may expand future production. Producing consumer goods raises current satisfaction without directly adding productive capacity.

Capital goods raise productivity when they allow workers to produce more output per unit of time or enable production that was previously impossible. This can increase an economy's productive potential and shift its PPF outward.

Investment in effective machinery, infrastructure or technology increases the quantity or quality of capital per worker. Output per worker can rise, unit costs may fall, firms can expand, and the economy can produce more capital and consumer goods in future.

Resources used for investment cannot produce current consumer goods at the same time, so faster future growth may require a short-run opportunity cost. The gain also depends on complementary skills, maintenance, demand and whether the capital is well chosen.

Specialisation concentrates production on a narrower range of outputs or tasks. Division of labour applies this within production by breaking the process into tasks and assigning workers to specialise in particular stages.

Adam Smith used pin production to show how task specialisation, saved switching time and purpose-designed machinery could raise output dramatically. For a firm, the gain is strongest when demand is large enough to support repeated specialised tasks.

A specialised producer can sell output for money and use the proceeds to buy many other goods, rather than barter directly with someone who wants that exact output. Reliable prices, saving and credit therefore make exchange across specialised households and firms easier.

Financial markets connect savers, borrowers, investors and traders, allowing funds and financial claims to move to different uses across time and risk.

By moving funds from savers to productive borrowers, markets can support capital formation and exchange. Their usefulness depends on information, trust, liquidity and prudent risk management.

Real economies lie on a spectrum. The size of government spending alone does not fully classify a system; ownership, regulation and how key resource decisions are made also matter.

Neither label determines every outcome. Performance depends on competition, institutions, information, incentives, administrative capacity and which goods are being allocated. Most economies combine the systems to capture some benefits and limit some failures.

In a mixed economy the state influences resource allocation alongside markets. It sets the legal framework, raises revenue, spends, produces or funds services, and changes incentives through policy.

Intervention can improve access, equity or efficiency, but it uses scarce public funds and may create administrative costs, weak incentives or unintended effects. The case for a policy depends on the market problem, its design and the quality of government information.