Economics
04552026 syllabus

ECONOMICS · CHAPTER 3

Microeconomic decision makers

Explain how households, workers, firms and financial institutions make choices.

Full syllabus4 connected sectionsSyllabus-aligned guide

LEARNING OBJECTIVES

What you will be able to do

  • analyse money, banking, saving and borrowing
  • explain occupational choice and wage differences
  • calculate firm costs, revenue, productivity and profit
  • compare firm growth and market structures

AT A GLANCE

Syllabus0455Coverage2026Sections4LevelFull syllabus

INTRODUCTION · THE BIG IDEA

Explain how households, workers, firms and financial institutions make choices.

Microeconomics studies decisions made by individual consumers, workers and firms. Incentives matter, but choices also depend on information, constraints, risk and non-financial aims.

Firm decisions connect productivity and scale to cost, revenue, profit and competition.

01

SECTION 01

Money, banks, saving and borrowing

Core concept

Money avoids barter's need for a double coincidence of wants. Commercial banks accept deposits, provide payments, lend and offer financial services. Central banks issue currency, act for government and banks, oversee the financial system and may influence interest rates.

Households save more when income, interest incentives or uncertainty rise, but spend more when confidence and wealth rise. Borrowing decisions depend on interest, income, purpose, collateral and expected ability to repay.

Interest-rate effects
Rise in interest rateLikely response
Saversgreater reward for postponing spending
Borrowersloans cost more
Firmssome investment becomes less profitable
02

SECTION 02

Workers, wages and trade unions

Core concept

People choose occupations using wages, hours, security, conditions, location, training, promotion and personal satisfaction. Wage differences reflect demand and supply of labour, skill, qualifications, responsibility, risk, bargaining power and discrimination.

Labour demand is derived from demand for output and depends on productivity and wage cost. Labour supply depends on population, participation, migration, training and occupational mobility. Trade unions may negotiate pay and conditions but can also increase labour cost or conflict.

ORIGINAL STUDY DIAGRAMExplain a wage difference
1Compare labour demand
2Compare labour supply and skills
3Add conditions or bargaining
4Apply to both occupations
03

SECTION 03

Firms, production, costs and revenue

Core concept

Firms combine factors to produce output. Productivity is output per input. Fixed cost does not vary with output in the short run; variable cost does. Average cost may fall through internal economies of scale and rise through diseconomies.

Revenue depends on price and quantity. A firm may maximise profit, growth, market share, survival or social outcomes. Principal–agent problems can arise when managers' aims differ from owners' aims.

RULE 1
total cost = fixed cost + variable cost
RULE 2
average cost = total cost ÷ output
RULE 3
total revenue = price × quantity
RULE 4
profit = total revenue − total cost
RULE 5
labour productivity = output ÷ workers
Original worked example

Cost and profit

  1. A firm sells 500 units at $20 each, so revenue = $10 000.
  2. Fixed cost is $2500 and variable cost is $9 per unit, so total cost = 2500 + 4500.
  3. Profit = 10 000 − 7000.

Answer: Profit = $3000 and average cost = $14 per unit.

04

SECTION 04

Firm size, growth and market structure

Core concept

Firms grow internally or through merger and takeover. Horizontal integration joins firms at the same stage, vertical integration joins different production stages, and conglomerate integration joins unrelated activities. Growth can create economies of scale but may weaken control.

A competitive market has many firms, low barriers and strong rivalry; a monopoly has one dominant seller and high barriers. Monopoly may fund research and exploit scale, but can restrict output, raise price and reduce choice. Small firms survive through personal service, flexibility, niche demand and low overheads.

Integration types
TypeExample directionPossible purpose
Horizontalcompetitor at same stagemarket share and scale
Backward verticaltoward suppliersecure input and cost
Forward verticaltoward retailercontrol distribution
Conglomerateunrelated industrydiversify risk

QUICK CHAPTER SUMMARY

The ideas to carry forward

  • Household choices respond to income, interest, confidence and risk.
  • Wages reflect labour demand, supply and non-wage conditions.
  • Firm profit links revenue with all costs.
  • Growth and market power can create both efficiency and consumer risks.

QUICK REVISION CHECKLIST

Can you do each of these without your notes?

  • analyse money, banking, saving and borrowing
  • explain occupational choice and wage differences
  • calculate firm costs, revenue, productivity and profit
  • compare firm growth and market structures