Population, Migration and Human Development
What this domain tests
Population, Migration and Human Development connects demographic facts to spatial patterns and to the idea of development as capability. Expect numerical questions on density and growth, classification of migration, and explanations of why HDI differs from income.
Core rules and concepts
- Density: arithmetic density is population divided by total area; physiological density divides population by cultivable land; agricultural density divides the agricultural population by cultivable land. Each answers a different question.
- Growth: natural increase = crude birth rate minus crude death rate, expressed per 1,000. Net growth adds net migration. Doubling time is roughly 70 divided by the annual growth rate in per cent.
- Demographic transition: high stationary, early expanding, late expanding, low stationary and declining stages; fertility falls after mortality, producing a lag and a population explosion.
- Population composition: age-sex pyramid; a broad base means high fertility; a bulging working-age group can yield a demographic dividend only with jobs and skills.
- Migration: push factors (poverty, drought, conflict) and pull factors (jobs, education, safety). Ravenstein noted that most migrants move short distances, that migration is stepwise, and that rural-urban movement dominates. Distinguish voluntary and forced, internal and international, seasonal and permanent.
- Human development: HDI, developed by Mahbub ul Haq with Amartya Sen, combines life expectancy, schooling (mean and expected years) and GNI per capita at PPP. It is a geometric mean of three normalised indices.
Worked example
A country has CBR 24, CDR 8, immigration 3 per 1,000 and emigration 1 per 1,000. Natural increase is 16 per 1,000, or 1.6%; net migration is +2 per 1,000; growth is 1.8%, with doubling time about 70/1.8 = 39 years. If its GNI is high but life expectancy and schooling are low, HDI remains modest because the geometric mean penalises the weak dimension.
Traps
Do not use total population as density. Do not call HDI an arithmetic average. Migration is a flow, not a stock. A high sex ratio means more females per 1,000 males, not necessarily more females than males.