Life expectancy at birth

Topic: Human Development: Concept, Approaches and Measurement · NCERT: Class 12, Ch 2 "The World Population: Distribution, Density and Growth"; Class 12, Ch 3 "Human Development"

Meaning

Life expectancy at birth is the average number of years a newborn baby is expected to live, if the death rates of today stay the same for the rest of its life.

It is the health indicator of the Human Development Index (HDI). It shows whether people in a country have a real chance to live a long and healthy life. Low life expectancy is also a mark of the first stage of demographic transition.

Explanation

How it is worked out

• Start with today's death rates. Demographers take the death rate at each age (babies, children, adults, old people) in a given year.
• Apply them to an imaginary newborn.
• They assume a baby born today will face these same death rates at every age as it grows up.

• The average age at death that results is the life expectancy at birth.

• It is an estimate, not a forecast.

• It does not predict how long a real baby will live.

• If health care improves later, real babies will live longer than the figure says.

• Deaths of babies and small children pull it down a lot.

• A death at age 1 cuts off many more years than a death at age 70.
• So when fewer infants die, life expectancy rises fast.

Its place in the HDI

• The HDI has three dimensions: health, education and standard of living.
• Life expectancy at birth has been the health indicator in both methods:
• NCERT (original) method: health, knowledge and resources each carry an equal weight of one-third. A higher life expectancy means people have a better chance of living long, healthy lives.

• Present method (since HDR 2010): the education and income indicators changed, but life expectancy at birth stayed as the health indicator.

• It is the only HDI indicator that measures health.

From years to a health index

• Goalposts (fixed minimum and maximum values) turn the years into a score between 0 and 1 [3]:
• Minimum ("natural zero"): 20 years. No country in the 20th century had a life expectancy below 20 years [3].

• Maximum ("aspirational target"): 85 years. This is a realistic target. Hong Kong, China (SAR), Monaco and San Marino have already gone above it in some years [3].

• Formula: Health index = (actual value − 20) ÷ (85 − 20).

• India, HDR 2025 (data for 2023): (72.0 − 20) ÷ (85 − 20) = 0.800 [4][3]
• Combining with the other dimensions:
• HDI = (Health index × Education index × Income index)^(1/3). This is the geometric mean (multiply the three values, then take the cube root).
• Because of this, a long life expectancy cannot fully make up for weak schooling or low income.

Link with demographic transition

• Demographic transition is the change a population goes through over time. It moves from high birth and death rates to low birth and death rates as a society becomes richer, more urban and more literate.
• First stage:
• Both birth and death rates are high, because of epidemics, famine, poor food and little health care.

• So life expectancy is low, and the population grows slowly.

• Later stages:

• Better medicine, clean water and more food bring death rates down.
• Life expectancy rises, and the population grows fast until birth rates also fall.

Where it occurs

• India:
• 72.0 years in 2023, up from 58.6 years in 1990 [4][2].
• This gives India a health index of 0.800. That is India's strongest HDI dimension. Its education sub-index is only about 0.59 [4][3].

• The national average hides gaps between states. For example, Kerala does much better than Bihar on human development.

• World:

• Hong Kong, China (SAR), Monaco and San Marino have gone above 85 years in some years. That is why 85 years is the upper goalpost [3].

• No country in the 20th century had a life expectancy below 20 years. That is why 20 years is the lower goalpost [3].

• Who uses it: the UNDP (United Nations Development Programme), set up in 1965 with headquarters in New York. It publishes the yearly Human Development Report, started in 1990 by Mahbub ul Haq with Amartya Sen.

Don't confuse with

• Life span: the greatest age a human body can live to. Life expectancy is an average based on today's death rates, not the upper limit.
• Health index (HDI): the 0–1 score made from life expectancy using the 20–85 goalposts. For India in 2023, life expectancy is 72.0 years but the health index is 0.800 [4][3].
• Expected years of schooling (EYS): also an "expected" figure for a child, but it is an education indicator. It measures years of school (goalpost 0–18), not years of life [3].
• Crude death rate: the number of deaths per 1,000 people in a year. It is a yearly rate, not a number of years. Death rates are used to work out life expectancy.

Prelims Hooks

• Life expectancy at birth is the only health indicator in the HDI. It was used in the NCERT method and is still used after HDR 2010.
• Goalposts in HDR 2025: minimum 20 years, maximum 85 years [3].
• Trap: the 85-year maximum is not out of reach. Hong Kong, China (SAR), Monaco and San Marino have gone above it in some years [3].
• India (HDR 2025, 2023 data): life expectancy 72.0 years, health index 0.800 [4][3]. It was 58.6 years in 1990 [2].
• Health index formula: (actual − minimum) ÷ (maximum − minimum). No log is used. Only the income index uses a natural logarithm [3].
• Low life expectancy, with high birth and death rates, marks the first stage of demographic transition.

Mains Points

• India's health gains are real but uneven:
• Life expectancy rose from 58.6 to 72 years between 1990 and 2023 [2]. This helped India's HDI rise from 0.446 to 0.685 [5].
• Health (index 0.800) is now India's strongest dimension. Mean years of schooling (6.9 years, sub-index 0.46) is the weak link [4].

• To reach the "high" HDI category (≥ 0.700), India needs continued health gains along with more schooling and faster income growth [2].

• The national average hides regional gaps:

• States such as Kerala do far better than states such as Bihar. Tribal areas also lag behind the rest of India.

• Policy needs to target infant and child deaths, nutrition and primary health care in lagging regions. These raise life expectancy the fastest.

• Health spending lifts human development, not income alone: Sri Lanka (rank 89) is in the "high" HDI group even though its income is lower than many richer countries. This shows that putting money into health and education can lift human development more than income growth alone [4].

Related concepts

• Human Development Index
• Adult literacy rate
• Gross enrolment ratio
• Purchasing power parity
• United Nations Development Programme
• Human Development Report

Read more

• Measuring human development: the HDI and the Human Development Report