Cambridge IGCSE Economics: Causes, consequences and policies of economic growth (0455)

This guide teaches sections 4.6.4, 4.6.5 and 4.6.6 of the Cambridge IGCSE Economics 0455 syllabus for examination in 2026: the causes of economic growth, its consequences in different economies, and the policies that promote it. Economics 0455 is not tiered, so everyone studies all of it. The countries and figures below are made up for practice and are not real statistics. Measuring growth and recession, and the supply-side measures themselves, are taught on a separate page (supply-side policy and measuring economic growth), so this guide does not repeat them.

Related pages: revision notes, practice questions, the Cambridge IGCSE Economics hub, the printable checklist and the free diagnostics.

What you must be able to do

Section	Outcome
4.6.4	Explain how a rise in total demand raises the use of resources and GDP, moving the economy from inside toward its PPC
4.6.4	Explain how growth shifts the PPC right, caused by investment, technology, and the quantity and quality of the factors of production
4.6.5	Explain the costs and benefits of growth in the context of different economies
4.6.6	Describe the range of policies that promote growth and judge how effective they might be

4.6.4 Causes of growth: two different things

The word growth hides two separate ideas. Keep them apart, because examiners reward the distinction.

	Using resources more fully	Making more resources or making them more productive
Position on the PPC diagram	Moves from a point inside the curve toward the curve	Moves the whole curve to the right
What changes	Utilisation of existing resources	The economy’s capacity to produce
Typical cause	A rise in total demand	Investment, technology, more or better factors
Time scale	Can be quick	Usually slow

A production possibility curve (PPC) is a line showing the most of two kinds of output that an economy can make from its resources when none are wasted. A point on the curve is full use. A point inside the curve means some resources are idle or poorly used. A point outside is not possible with today’s resources.

Total demand and the move toward the PPC

Total demand is all spending on the economy’s output: by households, firms, the government and foreign buyers. Suppose Country B (invented) can produce 1,000 units of real GDP when its resources are fully used. This is its potential output.

Worked example: a rise in total demand.

1. In year 1 firms sell only 800 units because spending is weak. Utilisation is 800 ÷ 1,000 × 100 = 80%. Spare capacity is 1,000 − 800 = 200 units.
2. The labour force is 50 million and 44 million are employed. Unemployment is (50 − 44) ÷ 50 × 100 = 12%.
3. In year 2 total demand rises, for example because exports increase and consumers spend more. Firms hire idle workers and run idle machines. Output rises to 950 units and employment to 47.5 million.
4. Utilisation is now 950 ÷ 1,000 × 100 = 95%. Unemployment is (50 − 47.5) ÷ 50 × 100 = 5%.
5. Real GDP rose by (950 − 800) ÷ 800 × 100 = 18.75%, with no new resources. The economy moved from a point well inside the PPC to a point close to it.

Limit. Once the economy reaches the curve, more demand cannot raise output further. Extra spending then pulls up prices instead, because no spare resources remain to meet it. Demand-led growth is therefore a one-off gain, not a lasting rise in capacity.

Shifting the PPC to the right

A lasting increase in capacity comes from four sources named in the syllabus.

Cause	How it raises potential output	Example
Investment	More capital goods (machines, factories, roads) raise what each worker can produce	A firm buys 20 new packing machines
Technology	Better methods give more output from the same inputs	Automated stock control in warehouses
Quantity of the factors	More land, labour or capital	Newly found mineral deposits; a rise in the working population; immigration
Quality of the factors	More productive workers or capital	Training programmes, better health, upgraded equipment

Net investment. Machines wear out. Gross investment is total spending on new capital. Depreciation is the value of capital used up. Net investment is gross investment minus depreciation, and only net investment adds to the capital stock.

Worked example: investment. Country B has a capital stock of 1,000 units. Gross investment is 120 and depreciation is 80.

1. Net investment = 120 − 80 = 40.
2. New capital stock = 1,000 + 40 = 1,040.
3. Increase = 40 ÷ 1,000 × 100 = 4%. If gross investment were only 80, net investment would be zero and the capital stock would not grow.

Worked example: quality and quantity of labour. Country C (invented) has 20 million workers producing 400 units of real GDP at full employment. Output per worker is 400 ÷ 20 = 20.

1. A training programme raises output per worker by 5%: 20 × 1.05 = 21.
2. The labour force also rises by 2%: 20 × 1.02 = 20.4 million.
3. New potential output = 21 × 20.4 = 428.4 units.
4. Growth in potential output = (428.4 − 400) ÷ 400 × 100 = 7.1%. Notice that the two causes multiply, so the result is slightly more than 5% + 2%.

The PPC in words and numbers. Country A (invented) makes consumer goods and capital goods.

Consumer goods	0	40	70	90	100
Capital goods	100	90	70	40	0

A point such as 50 consumer goods and 50 capital goods lies inside the curve, so resources are not fully used. If every figure rises by 10%, the curve shifts right: the end points become 110 capital goods and 110 consumer goods, and the middle point (70, 70) becomes (77, 77). Two links are worth stating. First, choosing more capital goods now means fewer consumer goods now, which is an opportunity cost. Second, a bigger share of capital goods today shifts the curve outward tomorrow, so a country that invests heavily gives up consumption today to produce more in future.

4.6.5 Consequences of growth

Growth is usually welcomed, but it brings costs as well as benefits, and their size depends on the type of economy.

Benefits	Costs
Higher output and incomes can raise living standards	Pollution, climate damage and resource depletion
More jobs and lower unemployment	Congestion and pressure on housing
Higher tax revenue to spend on health, education and infrastructure	Gains may go mainly to the already rich, widening inequality
Less poverty in absolute terms	Structural unemployment as old industries decline
More choice and better products	Inflation if demand outruns capacity
Firms can invest and export more	Opportunity cost of current consumption if growth comes from investment
	More imports as incomes rise, which can worsen the balance of payments

Worked example: tax revenue. Country C taxes 25% of GDP. At 400 units, tax revenue is 400 × 0.25 = 100. After growth to 428.4 units it is 428.4 × 0.25 = 107.1, an extra 7.1 that can pay for schools or clinics.

Worked example: who gains? Country D (invented) has total income of 500. The poorest 20% of households receive 20 and the richest 20% receive 250. Total income grows by 10%, but the poorest group gains 3% and the richest 14%.

1. Poorest: 20 × 1.03 = 20.6. Richest: 250 × 1.14 = 285.
2. New total = 500 × 1.10 = 550.
3. Poorest share falls from 20 ÷ 500 = 4.0% to 20.6 ÷ 550 = 3.7%. Richest share rises from 50.0% to 285 ÷ 550 = 51.8%. So everyone is better off in money terms, yet the gap has widened. Averages hide this, which is why a country’s GDP can rise while many people feel no benefit.

Different economies, different weights

Type of economy	Benefits that matter most	Costs that matter most
Low-income, mostly farming	Escape from poverty, funds for basic health and education	Loss of farmland and traditional jobs, rapid urban crowding, loss of forests
Fast-industrialising	Many new jobs, rising exports	Heavy pollution, long working hours, widening gaps between regions
Rich, service-based	Funds for research and public services	Resource use per person is already high, congestion, slower growth to repeat
Resource-rich exporter	Large export earnings and tax revenue	Depletion of resources that cannot be replaced, dependence on one product

Evaluation. Ask three questions. Is the growth sustainable, meaning could it continue without destroying the resources it depends on? Who receives the gains? What is given up to get the growth? A reasoned answer weighs costs and benefits for a named type of economy and reaches a judgement, rather than listing both columns.

4.6.6 Policies to promote growth and their effectiveness

Policy can aim at demand (to close the gap between actual and potential output) or at capacity (to shift the PPC). Section 4.5 covers the supply-side measures in full; here you only need to judge how well each might raise growth.

Policy	How it promotes growth	Possible limits
Fiscal: more government spending on roads, ports, schools	Raises demand now and capacity later	Widens the budget deficit; takes time; can be wasted
Fiscal: lower taxes on firms or households	More spending and more incentive to invest	Lower revenue; savers may not spend; benefits may go to the better off
Monetary: lower interest rates	Borrowing becomes cheaper, so firms invest and households spend	Little effect if confidence is low; can raise inflation; takes months to work
Monetary: a lower exchange rate	Exports become cheaper abroad	Imported raw materials cost more
Supply-side: education, training, deregulation, lower direct taxes, incentives to work and invest	Improves quality of labour and capital, so the PPC shifts right	Slow; costly; results uncertain
Encouraging foreign firms to invest	Brings capital, technology and jobs	Profits may leave the country; local firms may lose out
Trade agreements and fewer trade barriers	Bigger markets for exports; cheaper capital goods	Some home industries cannot compete
Stable laws, property rights and low corruption	Gives firms confidence to invest	Hard to achieve quickly

Worked example: comparing two projects. A government can build a road at a cost of 60, which raises output by 9 each year. A training scheme costs 30 and raises output by 4.5 each year.

• Road: annual return = 9 ÷ 60 × 100 = 15%; payback = 60 ÷ 9 = 6.7 years.
• Training: annual return = 4.5 ÷ 30 × 100 = 15%; payback = 30 ÷ 4.5 = 6.7 years. The returns match, so cost alone does not decide. The scheme that is cheaper uses less of the budget; the road may help a wider group of firms.

Worked example: cost to the budget. Country C plans to spend 160 and expects revenue of 140. The deficit is 160 − 140 = 20, which is 20 ÷ 400 × 100 = 5% of GDP. Extra spending of 10 on infrastructure raises the deficit to 30, which is 7.5% of GDP. Growth may later raise revenue, but borrowing has to be repaid and interest paid.

How effective is a policy? Test it with these questions.

1. Is the economy below potential (demand policy works) or at capacity (only supply-side policy lifts output)?
2. How long is the delay before the effect appears?
3. What does it cost, and what else could that money do (opportunity cost)?
4. Does it cause side effects such as inflation, debt or a trade deficit?
5. Does it suit the country’s stage of development and its institutions?

Common errors

• Describing a rise in demand as a shift of the PPC. It is a movement toward the curve.
• Saying that investment alone shifts the PPC without mentioning that it must exceed depreciation.
• Listing costs and benefits without naming the economy or deciding which outweighs the other.
• Calling any growth good. Growth that damages resources, or reaches only a few, may not raise living standards for most people.
• Proposing a policy without a limit. Every policy has a delay, a cost or a side effect.

Official syllabus

Aligned to the Cambridge IGCSE Economics 0455 syllabus for examination in 2026, published by Cambridge University Press & Assessment (Cambridge Assessment International Education), sections 4.6.4 to 4.6.6.