Diagnose growth
Distinguish actual from potential growth and identify positive and negative output gaps using AD/AS analysis.
Economic Growth and Sustainability
This chapter extends the earlier study of economic growth by separating actual from potential growth, analysing output gaps and the business cycle, evaluating policies that raise productive capacity, and asking whether growth is inclusive and environmentally sustainable.
Actual & potential growthOutput gapsBusiness cycleAutomatic stabilisersGrowth policiesInclusive growthSustainable developmentEnvironment
What this chapter prepares you to do
Read the cycle
Explain recession, recovery, boom, peak and slowdown, and show how automatic stabilisers moderate fluctuations.
Evaluate growth policy
Assess supply-side strategies, institutional conditions, the Washington Consensus and policies aimed at inclusive growth.
Judge sustainability
Explain the environment's resource, amenity and waste-absorption functions and evaluate the conflict between growth and environmental protection.
High-grade habit: distinguish actual growth from potential growth. A rise in real GDP can simply close a negative output gap; only an increase in productive capacity shifts the economy's potential output.
Chapter sections
25.1
Economic growth and the output gap
Actual economic growth is the observed increase in real GDP or real GNI. Potential economic growth is an increase in the economy's productive capacity — the level of real output that could be produced when resources are effectively used at full employment.
Textbook idea made simple
If firms bring idle workers and machines back into use after a recession, actual GDP can rise without productive capacity increasing. By contrast, more capital, improved skills or better technology raises the economy's potential output.
Actual growth
Real GDP rises. This can occur because previously idle resources are brought back into use, so the economy moves closer to its existing capacity.
Potential growth
The economy's capacity itself rises, for example through more capital, better technology, higher labour productivity or an expanded effective workforce. On AD/AS diagrams this is represented by a rightward shift of LRAS.
The output gap
The output gap is the difference between actual real GDP and potential real GDP.
Negative output gap
Actual real GDP is below potential GDP. There is unused capacity: unemployment may be above its full-employment level and some capital may be idle.
Positive output gap
Actual real GDP is temporarily above the sustainable full-employment level. Firms may be stretching capacity through overtime or unusually intensive use of capital. This cannot persist indefinitely.
A negative output gap
Actual real GDP is Y0, below the full-employment level YFE. The horizontal distance between them is the negative output gap, showing unused capacity and unemployment.
Adapted from the Cambridge International AS & A Level Economics book by Peter Smith (Second Edition, with Adam Wilby and Mila Zasheva).
A positive output gap
Actual real GDP Y0 is temporarily above YFE. The economy is operating beyond its sustainable capacity, for example through overtime, so cost and inflationary pressure is likely to emerge.
Adapted from the Cambridge International AS & A Level Economics book by Peter Smith (Second Edition, with Adam Wilby and Mila Zasheva).
Adjustment matters: a negative gap may close as wages and costs adjust and SRAS moves right, or policy-makers may stimulate AD if they believe adjustment will be too slow. A positive gap cannot be maintained indefinitely; overtime and unusually intensive use of capital eventually create cost and price pressure.
Exam distinction: a negative output gap is not the same as negative economic growth. GDP can be growing during a recovery while still remaining below potential output.
25.2
The business (trade) cycle
The business cycle is the fluctuation of actual real GDP around its underlying trend over time. Growth is therefore rarely smooth.
RecessionReal GDP falls.
→TroughThe fall in GDP reaches its lowest point.
→RecoveryGDP begins to rise, often while output is still below trend.
→BoomGDP grows strongly and may rise above trend.
→PeakThe expansion reaches its high point.
→Slowdown / slumpGrowth weakens and may turn into another recession.
The business cycle
Actual GDP fluctuates around trend GDP, passing through recession, trough, recovery, boom, peak and slowdown. Output can therefore be below or above its trend level at different stages of the cycle.
Adapted from the Cambridge International AS & A Level Economics book by Peter Smith (Second Edition, with Adam Wilby and Mila Zasheva).
Why cycles can occur
Changes in technology, investment, consumer demand and expectations can start expansions or contractions. The multiplier and accelerator can reinforce these movements: rising demand can encourage investment and further spending, while weakening demand can produce the reverse.
Textbook example
A technological breakthrough can encourage firms to invest and consumers to spend, starting an expansion. As capacity becomes stretched and confidence later weakens, investment and spending can slow; multiplier and accelerator effects can then reinforce the downturn.
Automatic stabilisers
Automatic stabilisers are changes in government expenditure and revenue that occur automatically as the economy moves through the cycle, without a new discretionary policy decision.
During recession
Unemployment and other benefit payments rise, while income-tax and sales-tax receipts fall. The budget moves toward deficit, partly supporting aggregate demand.
During a boom
Benefit spending tends to fall and tax receipts rise. The budget moves toward surplus, which automatically withdraws some demand from the economy.
Their main advantages are speed and low administrative delay: they begin to operate as economic activity changes, rather than waiting for policymakers to recognise the problem, design a response and implement it.
The effect of automatic stabilisers
A fall in AD from AD0 to AD1 reduces output. Higher benefit payments and lower tax receipts automatically support spending, partly offsetting the fall in demand towards AD2.
Adapted from the Cambridge International AS & A Level Economics book by Peter Smith (Second Edition, with Adam Wilby and Mila Zasheva).
25.3
Policies to promote economic growth
The textbook identifies two broad sources of long-run growth: more or better factor inputs and greater efficiency in using them. Policies therefore aim to shift LRAS to the right.
Supply-side routes to growth
Physical capital
Encourage business investment by maintaining macroeconomic stability, access to credit and confidence about future demand.
Human capital & labour flexibility
Education, training and retraining can raise productivity and help workers move into expanding industries and occupations.
Infrastructure & technology
Transport, communications and R&D can reduce costs, improve connectivity and support technological progress.
A stable macroeconomic environment is part of this process. When inflation is controlled and firms can obtain credit, they can plan investment with greater confidence. Growth policy is therefore not isolated from fiscal and monetary policy: stability can support the private investment that adds to the capital stock.
Evaluation: distinguish a policy that raises current aggregate demand from one that raises potential output. Education, infrastructure and R&D can raise LRAS, but they normally involve long time lags and an opportunity cost because resources used for future capacity cannot simultaneously provide current services.
An increase in long-run aggregate supply
A successful increase in productive capacity shifts LRAS to the right. The economy can then sustain a higher level of real GDP, and a given level of aggregate demand places less upward pressure on prices.
Adapted from the Cambridge International AS & A Level Economics book by Peter Smith (Second Edition, with Adam Wilby and Mila Zasheva).
Evaluating supply-side policies
- Many policies work only after long time lags: schooling, retraining, infrastructure and innovation do not raise capacity immediately.
- Government spending on growth policies has an opportunity cost because resources could support current services instead.
- Labour-market flexibility can improve adaptation, but outcomes depend on whether workers are protected from exploitation and whether training is available.
- R&D creates a tension: competition policy may limit market dominance, yet large firms may have greater resources to finance research.
- A stable macroeconomic environment matters because high inflation and uncertainty can deter investment.
The Washington Consensus
The textbook presents the Washington Consensus as a set of ten policy ideas associated with promoting growth and development:
- Fiscal discipline
- Reordering public expenditure priorities
- Tax reform
- Liberalising interest rates
- A competitive exchange rate
- Trade liberalisation
- Liberalising inward foreign direct investment
- Privatisation
- Deregulation
- Secure property rights
Why the same package may not work everywhere
The effectiveness of these measures depends on institutions and functioning markets. Some less developed countries may have weak or incomplete financial markets, poor governance, insufficient administrative capacity, weak infrastructure or vulnerability to exploitation when markets are opened. Strong institutions, social safety nets and targeted poverty reduction may therefore be necessary alongside market reforms.
Inclusive growth
Inclusive growth is growth whose benefits are distributed more widely and that creates opportunities across society, rather than concentrating gains in a small group.
Building sustained growth
- Macroeconomic stability
- Human capital and physical infrastructure
- An enabling environment for competition and trade
- A stronger financial system
- Structural transformation
- Technology and innovation
- Strong institutions
- Environmental sustainability
Making growth inclusive
- Early childhood development
- Conditional cash-transfer programmes
- Universal access to good-quality education
- Universal healthcare
- Infrastructure connecting poorer regions
- Income-earning opportunities for poorer households, including access to finance
Evaluation: a high GDP growth rate does not by itself prove that living standards have improved for everyone. Examine distribution, access to services, employment opportunities and whether the growth can be sustained.
25.4
Sustainable economic growth
Sustainable development means meeting present needs without undermining the ability of future generations to meet their own needs. The central question is whether today's growth reduces the environmental capital available to the future.
Three functions of the environment
1. Resources
The environment supplies natural resources and energy inputs used by firms, including both renewable and non-renewable sources.
2. Amenities
Clean air, beaches, forests, parks and attractive landscapes contribute directly to household utility and quality of life.
3. Absorber of waste
Production and consumption generate waste. The environment receives and processes some of it, but its absorptive capacity is limited.
Three functions of the environment
The environment supplies resources to firms and amenities to households, while also acting as an absorber of waste created by production and consumption. Sustainable growth requires all three functions to be protected.
Adapted from the Cambridge International AS & A Level Economics book by Peter Smith (Second Edition, with Adam Wilby and Mila Zasheva).
Growth and environmental externalities
Rapid industrialisation can increase energy demand, pollution, greenhouse-gas emissions, deforestation and pressure on natural resources. These are often negative externalities because producers and consumers do not bear all the social costs. When environmental effects cross national borders, unilateral policy is less effective and international cooperation becomes important.
Textbook context
The chapter uses rapidly industrialising economies such as China and India to illustrate the tension. Faster growth can reduce poverty and raise living standards, but it can also increase energy use and emissions. The policy problem is therefore not simply “growth or no growth”, but how to make growth compatible with environmental sustainability.
Policies for sustainable growth
Use resources more carefully
- Develop renewable and cleaner energy technologies.
- Increase energy efficiency and encourage cleaner transport.
- Protect forests and replant where possible.
- Set and enforce limits on resource depletion such as overfishing.
Reduce pollution and waste
- Regulate emissions and environmental standards.
- Use market-based incentives such as tradable pollution permits where appropriate.
- Encourage less harmful packaging and reduce non-biodegradable waste.
- Coordinate policy internationally where externalities cross borders.
The development dilemma
For poorer economies, growth can be essential to reduce poverty and improve health, education and living standards. Yet industrialisation can increase environmental damage. This creates a difficult intergenerational and international trade-off: slowing growth may protect environmental capital, but can delay urgently needed improvements in current living standards.
Exam evaluation: avoid treating growth and sustainability as simple opposites. The outcome depends on the technology used, regulation, resource management, institutions, income distribution and whether present investment creates cleaner productive capacity for the future.
Chapter 25 revision checklist
□ Distinguish actual and potential economic growth.
□ Define the output gap.
□ Explain a negative output gap using AD/AS.
□ Explain a positive output gap using AD/AS.
□ Explain why a positive output gap is not sustainable indefinitely.
□ Define the business/trade cycle.
□ Identify recession, trough, recovery, boom, peak and slowdown.
□ Relate the business cycle to positive and negative output gaps.
□ Explain automatic stabilisers in a recession.
□ Explain automatic stabilisers during a boom.
□ Explain how capital investment can raise potential growth.
□ Explain the roles of human capital, infrastructure and R&D.
□ Evaluate the time lags and opportunity costs of supply-side policy.
□ Recall the main Washington Consensus policies.
□ Explain why institutions affect the success of market reforms.
□ Define inclusive growth.
□ Explain policies that can make growth more inclusive.
□ Define sustainable development.
□ Explain the three functions of the environment.
□ Evaluate policies for environmentally sustainable growth.
20 questions. Each answer is marked immediately with a short explanation of why it is correct or incorrect.