Population, inequality and economic structure
Population, inequality and economic structure: build the core model, apply it to evidence and qualify conclusions where outcomes depend on context.
9708 section 11.4; A Level. Checked against Cambridge's 2026–2028 Version 2 (latest version published December 2025) and 2029 Version 1 (published September 2026). Cambridge states that neither version has significant changes affecting teaching. Always follow the syllabus for the candidate's examination year.
Before you begin
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
How is a normalized Gini coefficient commonly calculated from a Lorenz curve?
What you will learn
- Interpret demographic measures, optimum population and urbanisation
- Calculate and interpret a Lorenz curve and Gini coefficient
- Compare employment structure and trade patterns across development levels
Core model and terms
Population structure changes with birth rates, death rates, infant mortality and net migration; causes include health, income, education, conflict and policy. Optimum population is a theoretical balance between population and resources or output, not a fixed number that can be read from population size alone. Urbanisation describes the share or movement of people in urban areas and may reflect jobs, services, rural conditions and city capacity.
Apply and evaluate
A Lorenz curve plots cumulative population against cumulative income or wealth; greater bowing from the line of equality indicates greater measured inequality. With normalized axes, Gini = 1 − 2A, where A is the area under the Lorenz curve. Economic structure records employment in primary, secondary and tertiary sectors. Trade patterns may shift as skills, productivity, infrastructure and comparative advantage change, but countries can follow different paths.
Pause and explain
Which statement best applies population, inequality and economic structure?
Worked example
The area under a normalized Lorenz curve is 0.34. Calculate the Gini coefficient and interpret the result without treating it as a complete welfare measure.
Show the worked solution
- Gini = 1 − 2(0.34) = 0.32
- The coefficient indicates measured income inequality
- It does not show poverty, public-service access or every household’s living conditions
Answer Gini = 1 − 2(0.34) = 0.32 → The coefficient indicates measured income inequality → It does not show poverty, public-service access or every household’s living conditions
Try a topic test
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Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
The area under a normalized Lorenz curve is 0.34. Calculate the Gini coefficient and interpret the result without treating it as a complete welfare measure.
Give me a hint
Use Gini = 1 − 2A and state what a higher value indicates.
Compare my reasoning
- Gini = 1 − 2(0.34) = 0.32
- The coefficient indicates measured income inequality
- It does not show poverty, public-service access or every household’s living conditions
Gini = 1 − 2(0.34) = 0.32 The coefficient indicates measured income inequality It does not show poverty, public-service access or every household’s living conditions
Look for these in your work
- Gini = 1 − 2(0.34) = 0.32
- The coefficient indicates measured income inequality
- It does not show poverty, public-service access or every household’s living conditions
A country’s infant mortality rate falls while life expectancy rises. Name one population change this may help explain and one other factor to inspect.
Give me a hint
Connect child survival to age structure, then consider fertility or migration.
Compare my reasoning
- More children survive into later ages
- The age structure may change over time
- Birth rates, migration and population size also affect the resulting structure
More children survive into later ages The age structure may change over time Birth rates, migration and population size also affect the resulting structure
Look for these in your work
- More children survive into later ages
- The age structure may change over time
- Birth rates, migration and population size also affect the resulting structure
Why can rapid urbanisation create both economic opportunities and pressure on services?
Give me a hint
Link movement to job matching and to infrastructure capacity.
Compare my reasoning
- Workers and firms can cluster near jobs and markets
- Housing, transport and water demand can rise faster than capacity
- Outcomes depend on planning and investment
Workers and firms can cluster near jobs and markets Housing, transport and water demand can rise faster than capacity Outcomes depend on planning and investment
Look for these in your work
- Workers and firms can cluster near jobs and markets
- Housing, transport and water demand can rise faster than capacity
- Outcomes depend on planning and investment
Employment shifts from primary work toward manufacturing and services. Explain one possible development link and one reason the pattern is not a universal rule.
Give me a hint
Connect productivity and job composition, then consider country-specific advantages.
Compare my reasoning
- Productivity growth can release workers from agriculture into higher-value activities
- Services and manufacturing may expand
- Resources, skills, institutions and trade opportunities differ across countries
Productivity growth can release workers from agriculture into higher-value activities Services and manufacturing may expand Resources, skills, institutions and trade opportunities differ across countries
Look for these in your work
- Productivity growth can release workers from agriculture into higher-value activities
- Services and manufacturing may expand
- Resources, skills, institutions and trade opportunities differ across countries
Common mistakes
- Claiming that the same population size is optimal everywhere or using a Gini coefficient as a complete measure of poverty or wellbeing.
What can you explain now?
How is a normalized Gini coefficient commonly calculated from a Lorenz curve?
Compare with the explanation
One minus twice the area under the Lorenz curve
The area is compared with the equality line and the result summarizes distributional inequality.
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Make it stick
Before moving on, explain the central idea in population, inequality and economic structure and state one condition that could change its effect.
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