Demographic structure

The essentials

Demography studies the size, growth, composition and distribution of a population. Formal demography deals with measurement, while social demography asks how social, economic and cultural factors explain population trends. Thomas Malthus argued that population grows in a geometric progression while food supply grows only arithmetically, so famine and disease act as "positive checks"; he also suggested "preventive checks" such as late marriage. Critics pointed out that technology raised food output and that poverty is often caused by unequal distribution rather than population alone.

The theory of demographic transition says societies move from high birth and high death rates (stage one), through a phase where death rates fall but birth rates stay high, causing a "population explosion" (stage two), to low birth and low death rates (stage three). India entered the second stage in the twentieth century; 1921 is often treated as the year after which population grew continuously.

Key points

• Birth rate and death rate are expressed per 1,000 population per year.
• Natural growth rate = birth rate − death rate (ignoring migration).
• Sex ratio (as used in India) = number of females per 1,000 males.
• Child sex ratio refers to the 0–6 age group; a falling child sex ratio signals sex-selective abortion and neglect of girls.
• Dependency ratio = (population aged 0–14 + population aged 65 and above) ÷ population aged 15–64 × 100.
• A falling dependency ratio with a large working-age group creates a demographic dividend, but only if jobs, health and education are available.
• Literacy rates differ sharply by gender, region and social group.
• India launched a national family planning programme in the early 1950s; the coercive sterilisation drive during the Emergency (1975–77) produced a backlash, and later the programme was renamed family welfare.

Exam tips

Practise computing the sex ratio and dependency ratio from given figures. Remember that a "young" population means a high share of children, not of working adults.

Common mistakes

Do not confuse the dependency ratio with the share of the elderly alone. A high sex ratio in India means more females, not more males.