Cambridge A Level Economics: Countries at different levels of development (9708) – Revision Notes

These notes condense section 11.4 (outcomes 11.4.1 to 11.4.3) of the Cambridge International AS and A Level Economics 9708 syllabus for examination in 2026, 2027 and 2028. Topic 11 is A Level content only. For full explanations and longer worked examples, read the study guide. All countries and figures here are invented for illustration.

Links: Cambridge A Level Economics hub, printable checklist, practice questions and the free diagnostics.

11.4.1 Population: formulas and definitions

Term	Formula or meaning
Birth rate	Live births divided by population, times 1,000
Death rate	Deaths divided by population, times 1,000
Natural increase	Birth rate minus death rate (divide by 10 for a percentage)
Infant mortality rate	Deaths under age one ÷ live births × 1,000
Net migration	Immigrants − emigrants (per 1,000 if a rate is asked for)
Population growth	Natural increase + net migration
Urbanisation level	Urban population ÷ total population × 100
Optimum population	Population giving the highest output per head (or living standard) with given resources, capital and technology

Method in steps for a population question

1. Write the base: whole population, or live births for infant mortality.
2. Convert each flow to a rate per 1,000.
3. Subtract to find natural increase, then add net migration.
4. Convert to a percentage if asked (per 1,000 ÷ 10).
5. State the units and the direction of change.

Worked reminder (Country A, invented). Population 500,000. Births 9,000, deaths 6,000.

• Birth rate = 9,000 ÷ 500,000 × 1,000 = 18.0. Death rate = 6,000 ÷ 500,000 × 1,000 = 12.0.
• Natural increase = 18.0 − 12.0 = 6.0 per 1,000 = 0.6%, or 3,000 people.

Causes to recall

Variable	Higher in low-income countries because	Falls with development because
Birth rate	Infant deaths are common, children give labour and old-age support, little female education, limited contraception	Opportunity cost of children rises, education and women’s work spread, pensions exist
Death rate	Poor water, sanitation, nutrition and healthcare	Better public health and incomes. It can stay near the birth rate in a rich country with an old population
Infant mortality	Poor sanitation, malnutrition, few clinics, low maternal education	Health spending, clean water, education
Net migration	Push factors such as low pay, joblessness and war cause emigration	Pull factors such as better pay and available work draw immigrants to richer countries

Chain for a typical early-development pattern: death rate falls first, birth rate stays high, natural increase rises, population grows quickly. Later the birth rate falls and growth slows. Population structure follows: young when birth rates are high, ageing when birth rates are low and life expectancy is long.

Net migration chain. Emigration of young workers: lost skills (brain drain), a smaller labour force, but remittances sent home. Immigration: larger labour force and output, but pressure on housing and services. Evaluate by scale, skills and time.

Optimum population

• Underpopulation: more people would raise output per head.
• Overpopulation: fewer people would raise output per head.
• Output per head peaks at the optimum, where the extra output from one more person equals the current average.
• The optimum moves with technology, capital, skills and resources.

Worked reminder. Population (millions) 10, 20, 30, 40: output 150, 360, 570, 640. Output per head: 15.0, 18.0, 19.0, 16.0. The optimum is 30 million. From 30 to 40 million the extra 70 gives 7 per head, below the average of 19.0, so the average falls. Better technology would move the whole output column up and could move the peak to the right.

Evaluation: hard to measure, ignores distribution and the environment, and the optimum changes over time.

Urbanisation

• Level = urban ÷ total population. It generally rises as farming productivity rises and industry and services grow.
• Push: low farm incomes, land shortage. Pull: jobs, schools, hospitals.
• Benefits: higher productivity, economies of scale, easier service provision. Costs: congestion, slums, pollution, strain on services.
• Evaluate: does job creation keep pace with migration?

Worked reminder. 3.2 million urban out of 8.0 million is 40%. If the urban population becomes 5.4 million of 9.0 million, the level is 60%.

11.4.2 Gini coefficient and Lorenz curve

Item	Rule
Axes	Cumulative income share (vertical) against cumulative population share (horizontal), poorest first
Line of equality	The 45-degree line
A	Area between the line of equality and the Lorenz curve
B	Area below the Lorenz curve
Gini	A ÷ (A + B) = 1 − 2B when axes run 0 to 1
Range	0 (equal) to 1 (one person has everything)

Method in steps from grouped data

1. Turn shares into cumulative fractions.
2. For each group: width × (y start + y end) ÷ 2.
3. Add to get B.
4. Gini = 1 − 2B.
5. Check: it must lie between 0 and 1, and a sagging curve must give a larger value.

Worked reminder. Shares by quintile: 10, 15, 20, 25, 30. Cumulative: 10, 25, 45, 70, 100. The sum of adjacent pairs is 0.10 + 0.35 + 0.70 + 1.15 + 1.70 = 4.00. B = 0.2 × 4.00 ÷ 2 = 0.40. Gini = 1 − 0.80 = 0.20.

From areas. If A = 0.15 and B = 0.35, then Gini = 0.15 ÷ 0.50 = 0.30.

Analysing Lorenz curves

• Curve closer to the line of equality: more equal.
• Curves that cross: the Gini may match even though the distributions differ. Compare the shares of the poorest 20% or 40%, and say where they cross.
• A policy that shifts the curve towards the line (progressive tax, transfers) lowers the Gini.
• Limits: the Gini ignores the level of income, can hide where the inequality sits, and depends on whether income or wealth, before or after tax, is used. Informal activity may go unmeasured.

11.4.3 Economic structure

Employment by sector

Sector	Examples	Pattern
Primary	Agriculture, mining	Largest share of jobs at low income, falls as income rises
Secondary	Manufacturing, construction	Share rises through middle income, may fall later
Tertiary	Retail, finance, health, education	Largest share at high income

Worked reminder. Employed workforce 5.0 million. Shares 50%, 20%, 30% give 2.5, 1.0 and 1.5 million. If the workforce later becomes 6.0 million with shares 25%, 25%, 50%, jobs are 1.5, 1.5 and 3.0 million. Primary jobs fell by 1.0 million (a fall of 40%) while secondary rose by 0.5 million and tertiary doubled.

Reasons for the shift: rising farm productivity releases workers, demand for food grows slowly as incomes rise (low income elasticity) while demand for manufactures and services grows faster, and investment goes to industry and services.

Evaluate: moving into informal, low-productivity services brings little gain. Compare each sector’s share of output with its share of jobs to see productivity. Employment shares alone cannot show living standards.

Pattern of trade

Level	Typical exports	Typical imports
Low income	Primary products	Manufactures, machinery, fuel
Middle income	Growing share of manufactures	Capital goods and components
High income	Manufactures and a large share of services	Wide range, much trade in similar goods with other rich countries

These are tendencies, not rules. A resource-rich country can have high income and primary exports.

Worked reminder. Country X exports 10 bn, 60% primary (6 bn). Country Y exports 50 bn, 6% primary (3 bn). If the price of primary goods falls 10% with volumes unchanged, X loses 0.6 bn (6.0%) and Y loses 0.3 bn (0.6%). Concentration on primary exports makes X far more exposed.

Must-know distinctions

• Birth rate (per 1,000 people) versus infant mortality rate (per 1,000 live births).
• Natural increase versus total population growth (which includes net migration).
• Optimum population versus maximum or largest population.
• A and B on the Lorenz diagram, and the formula A ÷ (A + B).
• Share of employment versus share of output in a sector.

Quick self-test

1. A country of 600,000 people has 18,000 live births in a year. What is the birth rate?
2. In a year 1,260 children die under age one and there are 21,000 live births. What is the infant mortality rate?
3. Birth rate 22, death rate 8 and net migration +3 per 1,000. Find natural increase and total growth as percentages.
4. A = 0.15 and B = 0.35 on a Lorenz diagram. Find the Gini coefficient.
5. Quintile income shares are 10, 15, 20, 25 and 30. Find the Gini coefficient.
6. In a country with 10 million workers, 2.5 million work in the secondary sector. What share is that?
7. Urban population is 3.2 million out of 8 million. What is the urbanisation level?
8. State one reason why birth rates fall as income rises.
9. Define optimum population.
10. Give one reason why a rich country might have a higher death rate than a poorer one.
11. Two Lorenz curves cross but give the same Gini. What does that show?

Answers

1. 18,000 ÷ 600,000 × 1,000 = 30 per 1,000.
2. 1,260 ÷ 21,000 × 1,000 = 60 per 1,000 live births.
3. Natural increase = 14 per 1,000 = 1.4%. Total growth = 17 per 1,000 = 1.7%.
4. 0.15 ÷ (0.15 + 0.35) = 0.30.
5. 0.20.
6. 25%.
7. 40%.
8. For example, women have more education and job opportunities, so the opportunity cost of children rises. Or lower infant mortality means families need fewer births.
9. The population that gives the highest output per head, or living standard, with given resources, capital and technology.
10. An older age structure means a larger share of people are in age groups where death is common.
11. Overall inequality is the same, but the distributions differ: one favours the poorest, the other the middle, so say where the curves cross.

Where marks are usually lost

• Using total population as the base for the infant mortality rate.
• Giving natural increase when asked for growth, leaving out net migration.
• Forgetting that per 1,000 must be divided by 10 to give a percentage.
• Stopping at B and quoting it as the Gini, instead of using 1 − 2B.
• Plotting or reading Lorenz curves with groups ordered richest first.
• Describing the sector shift without explaining why it happens or whether it signals development.
• Stating general trade patterns as if every country follows them.
• Listing causes of population change without linking them to development and judging which matters most.

Official syllabus

Cambridge International AS & A Level Economics 9708 syllabus for examination in 2026, 2027 and 2028, published by Cambridge University Press & Assessment (Cambridge International), section 11.4.