Demography & Vital Statistics

1. What this chapter covers, and how NEET PG actually tests it

Demography questions ask for the definition of an indicator, the current Indian figure, or which source supplies a particular statistic.

The organising principle is that almost every indicator is a fraction, and almost every error is a wrong denominator.

The numerator is usually obvious; the denominator is where the exam sets its traps.

Note that the perinatal rate is the one that uses total births, because stillbirths in the numerator must be represented in the denominator too.

2. The demographic cycle

Populations move through a predictable sequence, and knowing where India sits explains most of its health policy.

Death rates fall first because sanitation, nutrition and infection control act quickly, while birth rates fall later because they depend on education, female autonomy and changed expectations of child survival.

That lag between the two falls is the entire explanation for population explosion, and it is why India's population continued growing long after mortality came under control.

India is now in the late expanding phase moving toward low stationary, with fertility at replacement level but a population still growing because of momentum.

Population momentum means that a large cohort of young people continues to produce births even at replacement fertility, so growth persists for decades after the fertility target is reached.

3. Population structure

The population pyramid plots age and sex, and its shape summarises the demographic stage at a glance.

A broad-based triangular pyramid indicates high fertility, a barrel shape indicates an ageing stable population, and a narrowing base indicates fertility below replacement.

$\text{Dependency ratio}=\frac{\text{Population under 15}+\text{Population over 64}}{\text{Population 15 to 64}}\times 100$

India's dependency ratio is falling as the youth bulge enters working age, and this favourable window is the demographic dividend.

The dividend is a window rather than a guarantee, because it delivers economic benefit only if that working-age population is educated, healthy and employed.

India counts sex ratio as females per 1000 males, which is the reverse of the convention in most countries and a recurring source of error.

The Census of 2011 recorded a sex ratio of 943, a child sex ratio in the zero to six age group of 919, a density of 382 persons per square kilometre and literacy of 74 per cent.

The child sex ratio matters more than the overall ratio for policy, because it reflects recent sex selection and differential survival rather than historical patterns.

4. Fertility indicators

4.1 The main measures

Crude birth rate is live births per 1000 mid-year population, and it is crude precisely because most of that population cannot give birth.

General fertility rate refines it by using women of reproductive age, conventionally 15 to 49, as the denominator.

Total fertility rate is the average number of children a woman would bear if she experienced current age-specific rates throughout her reproductive life.

Gross reproduction rate counts only female children, and net reproduction rate additionally allows for mortality before the end of the reproductive period.

A net reproduction rate of one means exact replacement, since each woman is being replaced by exactly one surviving daughter.

Replacement level total fertility is about 2.1 rather than 2.0, and the extra fraction accounts for girls who die before completing reproduction and for the slight excess of male births.

4.2 India's fertility position

India's total fertility rate stood at 2.0 in the 2021 Sample Registration System report, having fallen from 2.3 in 2014.

Fertility is therefore below replacement nationally, though it remains above it in a few states, and the national population continues to grow through momentum alone.

The sex ratio at birth improved to 913 in 2021 from 899 in 2014, which is progress but remains well below the biological expectation of around 950.

5. Mortality indicators

5.1 Definitions that are commonly confused

The infant mortality rate is the classic index of a country's overall health status, because it responds to nutrition, sanitation, maternal health, obstetric care and infection control together rather than to any one of them.

Neonatal deaths now dominate infant mortality in India, which shifts the target from diarrhoea and pneumonia toward delivery care, prematurity and birth asphyxia.

Maternal mortality ratio uses live births as the denominator, so it is properly a ratio; maternal mortality rate, which uses women of reproductive age, is a different and less commonly used measure.

5.2 India's current figures

The Sample Registration System gives the following, with maternal mortality taken from its most recent Special Bulletin.

Maternal mortality is reported separately from the main annual report, in a Special Bulletin covering a three-year period, because maternal deaths are too few for a single year to give a stable estimate.

The most recent bulletin, covering 2021 to 2023, gives 88 per 100,000 live births, down from 93 for 2019 to 2021 and from 130 for 2014 to 2016.

That fall of more than forty points in under a decade is among the steeper declines recorded anywhere.

Crude birth rate is around 19 per 1000 and crude death rate around 7 in Sample Registration System reporting, giving a natural growth rate of a little over one per cent per year.

Life expectancy at birth is approaching 70 years and is consistently higher for women than for men, which is the near-universal pattern.

6. Where the numbers come from

Knowing the source is examined as often as knowing the figure, because each source can supply only certain things.

The Sample Registration System exists because civil registration was incomplete, and it uses dual recording, combining continuous enumeration by a local recorder with an independent half-yearly survey, so that each cross-checks the other.

That dual method is what allows it to produce national mortality rates that civil registration alone could not, and it is the reason it is the standard source for the infant and maternal mortality figures quoted above.

The census counts everyone but only once a decade, so it cannot supply rates that need continuous monitoring.

7. Family planning

7.1 Denominators again

An eligible couple is a currently married couple with the wife of reproductive age, conventionally 15 to 45 years, and there are roughly 180 to 190 such couples per 1000 population.

A target couple is one with a defined number of living children, historically two or three, at whom limiting methods are directed.

Couple protection rate is the percentage of eligible couples effectively protected against childbirth by any approved method.

Unmet need is the proportion of women who wish to postpone or stop childbearing but are not using contraception, and it identifies a service failure rather than a preference.

7.2 Judging a contraceptive method

$\text{Pearl index}=\frac{\text{Accidental pregnancies}\times 1200}{\text{Total months of exposure}}$

The Pearl index expresses failures per hundred woman-years of exposure, so a lower value means a more effective method.

Its weakness is that it assumes a constant failure rate over time, whereas most methods fail disproportionately in the first months while the couple is learning to use them.

Failure is also reported in two ways: method failure occurring despite correct use, and user failure arising from incorrect or inconsistent use.

Sterilisation, intrauterine devices and implants have low user failure because they do not depend on repeated correct action, which is why they outperform barrier and behavioural methods in real use far more than in trials.

India's contraceptive use is dominated by female sterilisation, which raises an equity question, since the burden falls almost entirely on women despite vasectomy being simpler and safer.

7.3 The methods themselves

Methods divide into spacing and terminal, and the division matters because national programme targets are set separately for each.

The copper intrauterine device works chiefly by a sterile inflammatory and spermicidal effect rather than by preventing implantation, which matters because the older explanation is a common misconception and a source of unnecessary objection.

Emergency contraception with levonorgestrel is most effective the sooner it is taken and remains usable up to 72 hours, while a copper device inserted within five days is the most effective option of all.

Lactational amenorrhoea provides reliable protection only when three conditions hold together: the infant is under six months, exclusively breastfed, and menses have not returned.

Vasectomy is quicker, cheaper and safer than tubectomy, and the no-scalpel technique reduces complications further, but it requires three months or about twenty ejaculations before the man can be declared sterile.

Tubectomy is effective immediately, which is one practical reason it dominates despite the greater operative risk.

8. Comparing populations fairly

A crude rate cannot be compared between two populations of different age structure, because age itself drives most mortality.

A retirement town will show a higher crude death rate than a university town regardless of how good its healthcare is.

Standardisation removes that distortion by applying one common age structure to both populations.

Direct standardisation applies the age-specific rates of each study population to a single standard population, and it requires those age-specific rates to be known.

Indirect standardisation applies the age-specific rates of a standard population to the age structure of the study population, and it is used when the study population's own age-specific rates are unreliable because the numbers are small.

Indirect standardisation yields the standardised mortality ratio, where a value above 100 means more deaths than the standard population would have produced.

9. Policy and survey findings

The National Population Policy of 2000 set the framework still in use, with an immediate objective of meeting unmet need for contraception and health infrastructure, a medium-term objective of bringing total fertility to replacement level, and a long-term objective of a stable population by 2045.

Its most important shift was away from demographic targets imposed on health workers and toward a target-free approach, because target-driven sterilisation campaigns had produced coercion and had damaged public trust in the programme.

The National Family Health Survey is the other pillar of Indian health data, and its fifth round is the reference set most examination questions draw on.

Its headline findings were a total fertility rate of 2.0, a contraceptive prevalence rate of about 67 per cent for any method, institutional deliveries near 89 per cent, and full immunisation coverage of children aged 12 to 23 months of about 76 per cent.

It also recorded, for the first time, more women than men in the population overall, at 1020 females per 1000 males, while the sex ratio at birth remained below the biological expectation.

That combination is not contradictory: the overall ratio reflects women's greater longevity, while the ratio at birth reflects sex selection, and the two therefore move for entirely different reasons.

Anaemia remained the most stubborn finding, affecting over half of women of reproductive age and more than two-thirds of young children, and it worsened rather than improved between the fourth and fifth rounds.

10. Worked examples

Example 1. A district reports 40 stillbirths and 60 deaths within the first week among 10,000 total births. What is the perinatal mortality rate?

Perinatal mortality includes both, so the numerator is 100. The denominator is total births, not live births, because stillbirths appear in the numerator. The rate is therefore 10 per 1000 total births.

Example 2. A country reaches a total fertility rate of 2.0 but its population keeps growing. Why?

Population momentum. A large cohort of young women is still entering reproductive age, so the absolute number of births stays high even though each woman is having fewer children. Growth continues for decades after replacement fertility is reached.

Example 3. Which source would you use for a reliable national infant mortality rate, and why not the Civil Registration System?

The Sample Registration System, because civil registration remains incomplete for both births and deaths in parts of India. The Sample Registration System uses dual recording with independent cross-checking, which is what makes its rates dependable.

Summary

Almost every indicator is a fraction, and almost every error is a wrong denominator.

Perinatal mortality uses total births because stillbirths appear in its numerator; infant and neonatal rates use live births.

Maternal mortality ratio uses live births, which is why it is a ratio rather than a rate.

Death rates fall before birth rates, and that lag is the whole explanation for population explosion.

India is in the late expanding phase, with fertility at replacement but growth continuing through momentum.

Population momentum keeps births high because a large young cohort is still entering reproductive age.

India counts sex ratio as females per 1000 males, unlike most countries.

The 2011 Census recorded a sex ratio of 943 and a child sex ratio of 919.

Dependency ratio compares those under 15 and over 64 with the working-age group, and its fall creates the demographic dividend.

The dividend is a window, not a guarantee, and requires education, health and employment to be realised.

Replacement fertility is about 2.1 rather than 2.0, allowing for girls who die before completing reproduction.

A net reproduction rate of one means exact replacement of each woman by one surviving daughter.

The 2021 Sample Registration System reports maternal mortality of 93, infant mortality of 27, neonatal mortality of 19, under-five mortality of 31, total fertility of 2.0 and sex ratio at birth of 913.

Maternal mortality has fallen 37 points from 130 in 2014 to 2016.

Infant mortality is the classic index of overall health status because it integrates so many determinants.

Neonatal deaths now dominate infant mortality, which shifts the priority to delivery and newborn care.

The census counts everyone every ten years; the Sample Registration System supplies continuous rates through dual recording.

An eligible couple has a wife aged 15 to 45, and there are about 180 to 190 per 1000 population.

Unmet need identifies a service failure rather than a preference.

The Pearl index is failures per hundred woman-years, and it assumes a constant failure rate, which understates early failures.

Long-acting methods outperform barrier methods in practice because they remove user failure.

The copper device works by a sterile inflammatory and spermicidal effect, not by preventing implantation.

Vasectomy needs three months or about twenty ejaculations before sterility can be declared; tubectomy is effective immediately.

Crude rates cannot be compared across populations of different age structure, so use direct standardisation when age-specific rates are known and indirect when they are not.

The National Population Policy of 2000 abandoned demographic targets for health workers in favour of a target-free approach, because target-driven campaigns had produced coercion.

The fifth National Family Health Survey recorded 1020 females per 1000 males overall alongside a low sex ratio at birth, because longevity and sex selection move the two figures independently.