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The birth lottery in numbers
About 132 million babies are born each year, and none of them chooses where. Yet the country already sets the odds for much of what comes next: how long a child is likely to live, whether they get through the first five years, how long they will stay at school. Here are those gaps in numbers, from UN, World Bank and UNESCO data for 186 countries.
Four groups of countries
The World Bank sorts countries into four groups by income per person: low, lower-middle, upper-middle and high. It is a blunt tool. Every group has rich and poor families, and a country moves from one group to another when a single number crosses a line. But for a first look at the world it works well.
The table compares the groups on five measures: how long people live, how many children die before age five, how long adults went to school, how many can read and write, and how much is produced per person. Each figure is the average for the whole group, weighted by population; child deaths are weighted by births.
| Indicator | Low income | Lower-middle | Upper-middle | High income | World |
|---|---|---|---|---|---|
| Share of world population | 9.4% | 36% | 38% | 17% | 100% |
| Share of world births | 19% | 46% | 25% | 9.4% | 100% |
| Life expectancy at birth | 65.2 years | 69.6 years | 76.1 years | 80.5 years | 73.5 years |
| Die before age 5, per 100 children | 6.5 | 4.5 | 1.4 | 0.5 | 3.7 |
| Average years of schooling, adults | 4.5 years | 6.9 years | 8.7 years | 12.8 years | 8.4 years |
| Can read and write, per 100 adults | 60 | 76 | 95 | ≈99 | ≈86 |
| GDP per person a year, at purchasing power parity | $2,590 | $10,400 | $25,500 | $69,500 | $25,400 |
| Children per woman | 4.5 | 2.7 | 1.5 | 1.4 | 2.2 |
Years of school are the average for adults aged 25 and over, so they describe the parents’ generation more than today’s children. GDP per person is the value of everything a country produces, divided by its people and adjusted for prices. It is not what a family takes home. ≈ partly estimated: some countries in the group have no published figure (literacy, for example, is not measured in most high-income countries), and the data use an estimate.
Between the poorest and the richest group, life expectancy differs by 15.2 years. A child born in a low-income country is 13 times as likely to die before age five as a child born in a high-income country. Adults in low-income countries went to school for 4.5 years on average; in high-income countries, for 12.8 years.
Where 100 babies are born
Now take 100 babies born on the same day and see which group of countries each of them is born in.
- Low-income countries 19
- Lower-middle income 46
- Upper-middle income 25
- High income 10
Low-income countries are home to 9.4% of the world’s people, but 19% of its births. High-income countries have 17% of the people and 9.4% of the births. Families tend to be larger where incomes are lower, so a newborn is more likely to be in a poor country than a randomly chosen person is.
For the game this matters directly. 1in8B draws your country by births, not by population, so these are your odds as well.
Who does not reach the age of five
Worldwide, about 3.7 in 100 children die before their fifth birthday. With 132 million births a year, that is about 4.94 million children. These deaths are spread very unevenly. Here are 100 of them, by the group of the country where they happen:
- Low-income countries 34
- Lower-middle income 56
- Upper-middle income 9
- High income 1
Low and lower-middle income countries have 66% of the world’s births and 89% of the deaths of young children. In high-income countries about 0.5 in 100 children die before five; in low-income countries, 6.5 in 100.
74% of these deaths happen in the first year of life. They also lower life expectancy the most: one death in infancy pulls a country’s average down as much as many deaths in old age.
The widest gaps between countries
Averages for groups smooth out a lot. Between single countries the distance is larger. The table shows the highest and the lowest value of each measure among the 186 countries. Values that are estimates rather than published statistics are left out.
| Indicator | Highest | Lowest |
|---|---|---|
| Life expectancy at birth | Hong Kong 85.5 years | Nigeria 54.6 years |
| Die before age 5, per 100 children | Nigeria 12 | Hong Kong 0.2 |
| Average years of schooling, adults | Germany 14.3 years | Niger 1.4 years |
| Can read and write, per 100 adults | Uzbekistan 100 | South Sudan 27 |
| GDP per person a year, at purchasing power parity | Singapore $163,400 | Burundi $1,250 |
A baby born in Hong Kong can expect to live 85.5 years; in Nigeria, 54.6 years. That is a difference of 30.9 years.
In Nigeria, about 12 in 100 children die before the age of five; in Hong Kong, 0.2 in 100. Adults in Germany spent 14.3 years at school on average, adults in Niger 1.4 years. GDP per person differs by a factor of 131: $163,400 in Singapore against $1,250 in Burundi.
At one end there are usually small, very rich places, at the other some of the poorest countries. Most babies are born somewhere in between, so for the odds of a typical newborn the group averages say more than the records.
The same group, different lives
Income explains a lot, but not everything. India and Nigeria are both lower-middle income countries. Life expectancy in India is 72.3 years, in Nigeria 54.6 years. Out of 100 children, 2.7 die before age five in India and 12 in Nigeria.
The same is true of Bangladesh and Pakistan, from the same group: life expectancy is 75 years and 67.9 years, and 3.1 and 5.6 children in 100 die before five.
Vaccination, clean water, care at birth, conflict, the position of women: much of what shapes these numbers is not measured by income. Inside each country there are gaps as well, between regions, between cities and villages, between rich and poor families. Our data are national averages, so they cannot show them.
What these numbers say and what they do not
Each number here is an average over millions of people. It describes odds, not the fate of a particular child. Many children born in the poorest countries grow up healthy and live long lives, and some children born in rich countries do not.
The figures are also a snapshot: the latest value for each country, mostly for 2023–2025. They do not show how quickly things are changing. For that you would need long series by year, and our data do not hold them.
This is the idea behind 1in8B. The game draws your country the way real births are spread, then lives a life with that country’s odds. One life is a story, not a statistic. After a few lives, the gaps in these tables start to feel real.
Sources
All figures are calculated from the data the game uses: the World Bank’s World Development Indicators (release of October 8, 2026) and the sources below. Values that are estimates rather than published statistics are left out of every “highest” and “lowest”.
- Life expectancy at birth, men and women: UN World Population Prospects 2024, via the World Bank’s World Development Indicators (SP.DYN.LE00.MA.IN, SP.DYN.LE00.FE.IN), 2024.
- Under-five mortality: UN IGME, via WDI (SH.DYN.MORT), 2024.
- Mean years of schooling, adults aged 25 and over: UNDP, Human Development Report 2025 (data for 2023).
- Adult literacy rate, ages 15 and over: UNESCO Institute for Statistics, via WDI (SE.ADT.LITR.ZS).
- GDP per person at purchasing power parity, current international dollars: World Bank, WDI (NY.GDP.PCAP.PP.CD), 2025; the IMF for a few countries.
- Total fertility rate, children per woman: UN World Population Prospects 2024, via WDI (SP.DYN.TFRT.IN), 2024.
- Income groups: World Bank country classification for fiscal year 2027.
- Population: WDI (SP.POP.TOTL), 2025.
- Births a year: population times the crude birth rate, WDI (SP.DYN.CBRT.IN), 2024.
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