Core: Population and economic development patterns
Population and economic development patterns
This core sub-unit compares global population distribution and the demographic and economic measures used to explain development patterns. SL questions often require interpretation of population pyramids, DTM stages and development indicators.
Core rules
- Distribution vs density: distribution is where people live; density is people per km². A country can have high density but uneven distribution.
- Fertility and mortality: total fertility rate (TFR) is average births per woman; replacement level is about 2.1. Infant mortality rate and life expectancy are sensitive mortality indicators.
- Natural increase = crude birth rate minus crude death rate per 1,000. Net migration must be added to explain total population change.
- Demographic transition model (DTM): Stage 1 high birth and death rates; Stage 2 falling death rates; Stage 3 falling birth rates; Stage 4 low stationary; Stage 5 declining populations in some countries.
- Pyramids show expansive, stationary or constrictive shapes and reveal dependency ratios.
- Development measures: GDP/GNI per capita, HDI (life expectancy, education, GNI per capita), Gini coefficient and Gender Inequality Index.
- Demographic dividend: a bulge in the working-age population can boost growth only if education, health and jobs absorb it.
Worked example
A country has TFR 4.8, life expectancy 58, high infant mortality, a broad-based pyramid and GNI per capita of US$1,200. Reasoning: it is in late Stage 2 or early Stage 3 of the DTM. High youth dependency strains schools and clinics. A demographic dividend is possible when that cohort reaches working age, but only with investment in education and employment. If fertility falls later, the window closes and the population ages.
Traps
- Confusing population density with distribution.
- Calling a country 'overpopulated' without reference to carrying capacity or technology.
- Treating economic growth as identical to development.
- Assuming the DTM is deterministic and ignores migration.