Cambridge IGCSE Economics: Microeconomic Decision Makers (0455)

This guide covers Topic 3: Microeconomic decision makers in Cambridge IGCSE Economics (0455), following the site’s existing guides to the basic economic problem and the allocation of resources. Where those two topics establish the foundations of scarcity, choice and how markets allocate resources, Topic 3 turns to the specific economic agents – households, workers, firms – who make the decisions those foundations describe.

Where this fits in 0455

Microeconomic decision makers is the third of the six topics that make up 0455, with eight sub-topics (3.1 to 3.8) spanning money and banking through to competitive and monopoly markets. It builds directly on the supply and demand analysis from Topic 2, applying it to specific real-world actors and institutions rather than markets in the abstract.

Syllabus coverage

CAMBRIDGE IGCSE ECONOMICS (0455) – TOPIC 3: MICROECONOMIC DECISION MAKERS

• 3.1 Money and banking: the forms, functions and characteristics of money; the role and importance of central banks and commercial banks for government, producers and consumers
• 3.2 Households: the influences on spending, saving and borrowing, including income, the rate of interest and confidence
• 3.3 Workers: factors affecting an individual’s choice of occupation (wage and non-wage factors); wage determination, including demand and supply, relative bargaining power and government policy such as a minimum wage; reasons for differences in earnings; division of labour/specialisation
• 3.4 Trade unions: definition; their role in the economy, including collective bargaining; the advantages and disadvantages of trade union activity
• 3.5 Firms: classification of firms; small firms; causes and forms of the growth of firms; mergers; economies and diseconomies of scale
• 3.6 Firms and production: demand for factors of production; labour-intensive and capital-intensive production; production and productivity
• 3.7 Firms’ costs, revenue and objectives: total, fixed and variable costs, average total, average fixed and average variable costs (marginal cost is not required), total and average revenue (marginal revenue is not required), and the objectives of firms: survival, social welfare, profit maximisation and growth
• 3.8 Market structure: competitive markets – the effect of having a high number of firms on price, quality, choice and profit (the syllabus notes that the theory of perfect and imperfect competition and diagrams are not required); monopoly markets – the characteristics, advantages and disadvantages of monopoly (diagrams are not required)

How to approach it

Because this topic spans several distinct economic agents, revision benefits from treating each – money and banking, households, workers, firms – as its own mini-topic with its own key definitions, rather than trying to hold the whole strand in mind at once. Exam questions frequently ask candidates to apply one agent’s decision-making to a given scenario, so practising with real or hypothetical case studies is more valuable than memorising definitions alone.

Official syllabus

Cambridge IGCSE Economics (0455) syllabus, for examination in 2026 – cambridgeinternational.org.

Households, workers and wage determination

A household’s spending, saving and borrowing decisions are shaped by factors including income level, interest rates, expectations about future prices, and the availability of credit. For workers, wage rates are determined by the interaction of labour demand (how many workers firms want to employ at a given wage) and labour supply (how many people are willing to work at that wage) – a shortage of workers with a particular skill tends to push wages up, while an oversupply tends to push them down. Trade unions can shift this balance by negotiating collectively on behalf of workers, using methods such as collective bargaining and, where necessary, industrial action, to pursue objectives like higher wages or better working conditions.

Costs, revenue and the difference between production and productivity

Production refers to the total output a firm creates, while productivity refers to output per unit of input (for example, output per worker) – a firm can increase production simply by hiring more workers without necessarily becoming more productive. Fixed costs do not change with the level of output (such as rent), while variable costs rise and fall with output (such as raw materials). Total cost is fixed cost plus variable cost; average total cost is total cost divided by output, and average fixed cost and average variable cost divide fixed cost and variable cost by output in the same way. Questions commonly ask candidates to identify which type of cost has changed in a given scenario. Marginal cost is not required for 0455: the syllabus guidance for 3.7.1 says so explicitly.

Money and banking, briefly

Money performs four widely recognised functions: a medium of exchange (avoiding the inefficiency of barter), a unit of account (allowing prices to be compared), a store of value (allowing purchasing power to be held over time), and a standard for deferred payment (allowing debts to be specified in monetary terms). Central banks oversee a country’s monetary system and typically set the base interest rate, while commercial banks accept deposits and make loans to households and firms. (Background, not required by 0455, whose 3.1.2 asks for the role and importance of central and commercial banks for government, producers and consumers: in lending, commercial banks create credit, since a loan made from deposited funds effectively increases the total money available in the economy beyond the original deposit.)

Worked example: a competitive market vs a monopoly

The comparison below is an original model written for this resource, not a reproduction of any official past paper or mark scheme. It follows syllabus 3.8.1, which asks for the effect of having a high number of firms on price, quality, choice and profit, and 3.8.2 on monopoly. The theory of perfect and imperfect competition, and market-structure diagrams, are not required for 0455.

Effect on    Many competing firms               Monopoly (one dominant supplier)

Price        Rivalry keeps prices down --        Can set a higher price, as buyers
             a firm charging more loses          have few or no alternatives
             customers to its rivals
Quality      Firms improve quality to win        Less pressure to improve, though
             and keep customers                  profits can fund research
Choice       Wide range of products and          Little or no choice
             suppliers
Profit       Competition tends to keep           Can earn high profits, protected
             profits lower                       by barriers to entry

A monopoly also has possible advantages: its large scale can bring economies of scale that lower average costs (which may or may not be passed on as lower prices), and its profits can finance research and development. A strong exam answer does not simply list these points but applies them to the market in the question – for example, explaining that a town with one bus operator leaves passengers no alternative if fares rise, then weighing whether the operator’s scale keeps its costs lower than several smaller operators could manage.

Common mistakes

Confusing production with productivity, particularly when a question describes a firm hiring more workers. Describing fixed and variable costs without linking them to a specific example from the scenario given. Treating “monopoly” as automatically illegal or banned, when the syllabus instead asks for its advantages as well as its disadvantages. Revising perfect and imperfect competition theory or market-structure diagrams for 3.8, which the syllabus says are not required. Explaining trade union objectives without naming the specific methods (such as collective bargaining) unions use to pursue them.

Quick revision checklist

• Be able to define and calculate total cost, fixed cost, variable cost, average total cost, average fixed cost and average variable cost, and identify each in a given scenario (marginal cost is not required).
• Explain how labour demand and supply interact to determine a wage rate.
• Explain the effect of having a high number of firms on price, quality, choice and profit, and give the characteristics, advantages and disadvantages of monopoly.
• Distinguish clearly between production (total output) and productivity (output per unit of input).
• Practise applying household, worker and firm decision-making to real or hypothetical case-study scenarios, since this topic is frequently tested through applied questions rather than pure recall.