A World of Inequality

The situation

We often hear statistics about poverty, education, population growth and health. But what do the figures actually mean? How can we compare countries and groups of people accurately? And what happens when a population grows faster than the services it needs?

In this unit, you will interpret real statistics, express them in different ways and consider some of their consequences. The figures are not just numbers: they describe people's opportunities and living conditions.

The statistics in this unit come from international organisations and are dated. They refer to different years and use different definitions; do not assume that every measure is directly comparable.

Fractions

A fraction describes a part of a whole.

We can use of to say what the fraction refers to:

• A quarter of the population lives below the poverty line.
• Two thirds of the children attend primary school.
• Three quarters of all households have access to electricity.

Percentages

Per cent means “out of every hundred”. We write 25% and say “twenty-five per cent”.

• 25% = a quarter
• 50% = a half
• 75% = three quarters
• 20% = a fifth
• 10% = a tenth

Proportions and shares

Other useful expressions include:

• a large / small proportion of
• the majority / a minority of
• almost half of; just over a third of; less than a quarter of
• account for; represent; make up

The World Inequality Report 2026 estimates the distribution of global income and wealth in 2025. The figures show that income and wealth are not distributed in the same way.

Figures are rounded. Income is not the same as wealth: income is money received over a period; wealth is the value of assets owned. The rounded income shares total 99%.

We can describe the figures in several ways:

• The richest tenth receives just over half of global income.
• The poorest half receives less than a tenth of global income.
• The richest 10% own three quarters of global wealth.
• The poorest 50% own only 2% of the world's wealth.

Access to safe water and sanitation has improved, but billions of people still lack services that many others take for granted.

• About 2.1 billion people lacked safely managed drinking water.
• About 3.4 billion people lacked safely managed sanitation.

Notice the different expressions:

• Nearly three quarters of the population had safely managed drinking water.
• More than a quarter did not.
• Just over half had safely managed sanitation.
• A little over two fifths did not.

“Safely managed” is a specific service standard. It does not mean that everyone outside this category has no water or no toilet at all.

UNESCO's 2026 Global Education Monitoring material reports that 273 million children and young people were out of school in 2024. That is about one in six of the relevant age groups worldwide.

“Completed on time” is important: some learners finish later. UNESCO estimates that eventual completion rates are higher when late completion is included.

Literacy

• About 754 million adults worldwide were unable to read and write in 2024.
• Women accounted for 63% of this number.
• Adult literacy was about 88% worldwide, but about 69% in sub-Saharan Africa.
• Youth literacy was about 93% worldwide and 79% in sub-Saharan Africa.

Algeria: a personal point of reference

A teacher who worked in Algeria in 1973 remembers the population being put at about 12 million. The World Bank's historical population series gives an estimate of about 14.8 million for that year. Its 2025 estimate is about 47.4 million.

On this consistent statistical series, Algeria's population is now a little more than three times its 1973 size. The remembered figure and the later historical estimate are not identical, but both illustrate the scale of change.

Population projections in selected African countries

The UN's 2024 population projections illustrate the rapid growth expected in several countries. These are projections, not certainties.

Doubling time

Doubling time is the approximate time it takes for a population to become twice as large, if its annual growth rate remains constant.

This is the Rule of 70: divide 70 by the annual growth rate to estimate the doubling time. It is a useful approximation, not a precise forecast.

Imagine a town with 20,000 people. Over a period of years, its population doubles to 40,000. What happens to the services the town needs?

These are imaginary figures to illustrate proportional change. They assume that the age structure and level of provision per person remain the same.

If one classroom holds 40 children, and the number of children doubles, the town may need a second classroom of the same size. It will also need more teachers, desks, books and other resources.

But population growth does not automatically double every need

The number of school-age children may not rise at exactly the same rate as the total population. The age structure matters. Better buildings, technology, organisation and productivity can also change how many services are needed.

Countries experiencing rapid population growth need more doctors, nurses and other health workers. However, some doctors trained in lower-income countries move to wealthier countries.

They may be attracted by higher salaries, better-equipped hospitals, specialist training and improved career opportunities. Their decisions are understandable, but large-scale migration can make shortages more serious in the countries they leave.

The World Health Organization warns that continued large-scale migration from countries with serious health-workforce shortages can widen inequalities in access to healthcare. It supports fair recruitment and cooperation between countries.

Useful statistical language:

• One in five doctors leaves the country.
• The number of doctors has fallen by a tenth.
• The population has increased by a third.
• There are fewer doctors per thousand people.
• The demand for medical care has grown faster than the supply of doctors.

These three ideas are easy to confuse:

• A number: 10 million people.
• A proportion: 10% of the population.
• A rate: population growth of 2% per year.

Compare these descriptions:

• The population increased by 50%: it became half as large again.
• The population increased to 150% of its former size: it also became half as large again.
• The population increased from 20% to 30%: a rise of 10 percentage points, or a 50% increase relative to the original 20%.

Choose the expression with the same meaning.

Choose the correct expression to complete each sentence.

Choose the correct expression.

Read the figures in the unit and choose the best interpretation.

Choose the best completion.

A town grows up

Twenty-five years ago, the town of Kitala had a population of 20,000. There was one primary school with ten classrooms, a small health centre and a weekly market. Most families lived in the older part of the town, and many people worked in agriculture.

Today, the population is approaching 40,000. The town has spread into the surrounding countryside. The original school has been extended, but it is still not large enough for all the children. A second school has opened, and the health centre has become a small hospital. The market is busier, and new shops and workshops have appeared.

Growth has brought opportunities as well as difficulties. There are more customers for local businesses, and more young people are looking for work. However, the town needs more houses, better roads and a more reliable water supply. Some families still live in crowded homes, and not all children can attend secondary school.

The town council has a difficult task. It must decide how to divide a limited budget. Should it build another school, improve the water supply, repair the roads or expand the hospital? Each project is important, but the council cannot afford to do everything at once.

The mayor says that population growth is not automatically a problem. “A larger population can bring more workers, ideas and customers,” she explains. “But we must invest in services and create opportunities. If the town grows without planning, the benefits will not be shared equally.”

Writing task: How unequal is our world?

Write a short report using at least five statistics from this unit. Include:

• one fraction and one percentage;
• one comparison between two groups or countries;
• one statistic about education, water or sanitation;
• one example of population growth and its consequences;
• a concluding comment about what the figures suggest.

Discussion

1. Which statistic in this unit surprised you most? Why?
2. What should a rapidly growing town provide first: schools, hospitals, housing, jobs or clean water?
3. How can a country encourage doctors and other skilled workers to stay?
4. Can population growth create economic opportunities as well as pressure on services?
5. Which statistics would you like to know about your own country?

• 25% is a quarter; 50% is a half; 75% is three quarters.
• We use of the when referring to a particular, identifiable group: “a third of the population”.
• We use of without an article for general groups: “a third of people”.
• Use twice as many with countable nouns and twice as much with uncountable nouns.
• A percentage-point change is different from a percentage change.
• A number, a proportion and a rate describe different things.
• Statistics need dates, definitions and careful interpretation.