Demography and its basic ideas
Demography is the study of population. Formal demography counts and predicts numbers (births, deaths, migration). Social demography asks why the numbers change: what social, economic and political causes lie behind them.
Population data comes mainly from the Census (every 10 years in India since 1881) and surveys like the National Family Health Survey. Planning schools, hospitals and jobs needs these numbers.
Malthus's theory of population growth
Thomas Robert Malthus (1798) said:
- Population grows in a geometric way: 1, 2, 4, 8, 16...
- Food grows in an arithmetic way: 1, 2, 3, 4, 5...
- So population will outrun food. It is controlled by positive checks (famine, disease, war) or preventive checks (late marriage, self-control).
Criticism: Europe's food and wealth actually grew faster than population, thanks to technology. Liberal and Marxist thinkers said poverty comes from unequal sharing of resources, not just from too many people.
Theory of demographic transition
Population growth is linked to economic development. There are three stages:
- Stage 1: high birth rate, high death rate. Growth is slow. Poor, farming society.
- Stage 2: high birth rate, falling death rate. Medicine and food improve, so deaths fall fast, but births stay high. This gap causes a population explosion.
- Stage 3: low birth rate, low death rate. Growth is slow again. Developed society.
India entered stage 2 after about 1921 (the 'year of the great divide') and is now moving towards stage 3.
Common measures: rates and ratios
- Birth rate: live births per 1000 people in a year.
- Death rate: deaths per 1000 people in a year.
- Rate of natural increase (growth rate): birth rate − death rate.
- Total fertility rate: average number of children a woman would have in her lifetime. About 2.1 is 'replacement level'.
- Infant mortality rate: deaths of babies under 1 year per 1000 live births.
- Maternal mortality rate: deaths of women in childbirth per 100,000 live births.
- Life expectancy: how many years a person is expected to live.
- Sex ratio: females per 1000 males. India's child sex ratio (0-6 years) has fallen, showing son preference and sex-selective abortion.
- Age structure: share of children (0-14), working age (15-64) and elderly (65+).
- Dependency ratio: (children + elderly) ÷ working-age × 100.
Demographic dividend
When the working-age share is large and the dependency ratio falls, a country can grow faster. This is the demographic dividend. It is only a chance: without jobs, health and education, young people may become unemployed instead.
Rural-urban links and divides
Most Indians still live in villages, but the urban share keeps rising.
Links
- Migration: people move to cities for work and send money home (remittances).
- Markets: farm produce goes to cities; factory goods reach villages.
- Media and transport: TV, phones and roads carry city lifestyles to villages.
Divides
- Farming gives less and less income; good jobs cluster in cities.
- Villages have fewer hospitals, colleges and services.
- Cities get crowded; many migrants live in slums with poor housing.
Rural distress (debt, low crop prices) pushes people out; city jobs pull them in.
India's population policy
- 1952: India became one of the first countries with a national family planning programme. Aim: slow growth, improve health.
- 1975-77 (Emergency): coercive (forced) mass sterilisation, mostly of poor men. It caused anger and set the programme back.
- After 1977: renamed the National Family Welfare Programme; focus moved to voluntary methods and mother and child health.
- National Population Policy 2000: aims include free, compulsory schooling till 14, lower infant and maternal mortality, universal immunisation, later marriage for girls, and reaching replacement-level fertility (TFR 2.1).
Lesson: people choose smaller families when they have health, education (especially of girls) and security, not when they are forced.
Key formulas and definitions
- Birth rate = (live births in a year ÷ total population) × 1000
- Death rate = (deaths in a year ÷ total population) × 1000
- Growth rate (natural increase) = birth rate − death rate (per 1000; ÷10 for %)
- Sex ratio = (number of females ÷ number of males) × 1000
- Dependency ratio = (people aged 0-14 + people aged 65+) ÷ people aged 15-64 × 100
- Infant mortality rate = (deaths under age 1 ÷ live births) × 1000
- Replacement-level fertility: TFR ≈ 2.1 children per woman
Worked examples
1. A town of 50,000 people had 1,000 births in a year. Find the birth rate.
Birth rate = 1000 ÷ 50000 × 1000 = 20 per 1000.
2. Birth rate is 20 and death rate is 7 per 1000. Find the growth rate in per cent.
Growth = 20 − 7 = 13 per 1000 = 1.3%.
3. A district has 500,000 males and 470,000 females. Find the sex ratio.
Sex ratio = 470000 ÷ 500000 × 1000 = 940 females per 1000 males.
4. A village has 300 children (0-14), 600 adults (15-64) and 100 elderly (65+). Find the dependency ratio.
(300 + 100) ÷ 600 × 100 = 400 ÷ 600 × 100 ≈ 66.7. About 67 dependants for every 100 working-age people.
5. In 1,000 live births, 30 babies die before their first birthday. What is the infant mortality rate?
IMR = 30 ÷ 1000 × 1000 = 30 per 1000 live births.
6. A country has a birth rate of 40 and a death rate that falls from 38 to 15. Which stage of demographic transition is this, and what happens to growth?
Stage 2 (high birth, falling death). Growth jumps from 40 − 38 = 2 to 40 − 15 = 25 per 1000: a population explosion.
Common mistakes
- Adding birth and death rates. Growth rate = birth rate MINUS death rate.
- Writing sex ratio as males per 1000 females. In India it is females per 1000 males.
- Thinking demographic dividend is automatic. It needs jobs, health and education for the young.
- Saying population explosion happens because births rise. It happens because deaths fall while births stay high.