Measuring Global Inequalities
What is Development?
Development describes how a country becomes ‘better off’ for its citizens — not just richer, but healthier, better educated, better governed and more equal. Geographers measure development to compare countries, track progress over time and direct aid where it is most needed. The challenge is that development has many faces, and any single number captures only part of the picture. Theme 6 starts with this puzzle: how do we measure something so complex without losing the detail?
The two most common economic measures are GNI (Gross National Income) and GDP (Gross Domestic Product). Both express national wealth in US dollars per person, but neither tells you how wealth is shared, how long people live or how many can read.
Gross Domestic Product (GDP)
Gross Domestic Product (GDP) is the total value of goods and services made within a country’s borders in a year. Divide by population and you get GDP per capita, which lets you compare countries of different sizes. The UK’s GDP per capita in 2025 sat at around US$58,000; Bangladesh’s at about US$2,600; the United States at about US$90,000. GDP captures economic output well but ignores anything happening outside markets — unpaid care work, subsistence farming, environmental damage — so a country with rapid GDP growth can still be polluting its rivers and overworking its citizens.
Gross National Income (GNI)
Gross National Income (GNI) — the headline measure in this topic — is broader than GDP. It counts everything earned by a country’s residents, including profits and wages flowing in from overseas. For countries with lots of citizens working abroad (such as the Philippines, where remittances were about US$38 billion in 2023, equal to 9% of GDP), GNI is meaningfully larger than GDP. The World Bank uses GNI per capita to classify countries: low-income (under US$1,145), lower-middle, upper-middle and high-income (over US$14,005 in 2024).
Total GDP can be misleading. China’s GDP (about US$19 trillion in 2025) is roughly five times the UK’s — but China has 20 times more people. Per-capita figures (GDP / population) flip the comparison: UK GDP per capita is about US$58,000 versus China’s US$14,000. China is the world’s second-largest economy in total terms and a middle-income country in per-person terms. Both stories are true, and a strong answer shows both at once.
Limitations of Single Numbers
Wealth measures hide three big problems. Inequality: GNI per capita is an average. South Africa’s upper-middle income status conceals one of the world’s widest wealth gaps — the richest 10% earn 65% of national income. Informal economies: in much of sub-Saharan Africa, around 85% of jobs are informal (street markets, smallholder farming, casual labour) and are missed from GDP entirely. Quality of life: numbers say nothing about life expectancy, schooling, freedom or safety. Cuba’s GNI per capita is only US$9,500 but Cubans live to 79 on average — longer than far richer countries. To capture these, geographers use composite measures alongside money.
Composite Measures & the Development Continuum
The Human Development Index (HDI) combines GNI per capita, life expectancy and average years of schooling into a single 0-to-1 score. Norway sits near the top at 0.97; the UK at 0.94; India at 0.64; South Sudan near the bottom at 0.39. Other useful measures include literacy rates, doctors per 1,000 people, infant mortality and access to safe water. Together, these data points form a development continuum — a sliding scale, not a binary split. The simple ‘rich North, poor South’ map of the 1980s no longer fits a world where China, India and Brazil are catching up fast.
The development gap is the difference in living standards between richer and poorer countries. It is dynamic: in 1990, China’s GNI per capita was less than 5% of the UK’s; by 2024 it was around 25%. Vietnam moved from low-income to lower-middle income within thirty years. But other countries have stalled: South Sudan’s HDI has barely moved since 2011 because of conflict. The gap is closing in some places and widening in others — one reason geographers prefer the continuum to the old binary classification.
GDP per capita is a useful starting point but masks inequality (averages hide gaps), excludes informal economies (a huge share of work in many LICs), and ignores life expectancy, schooling and well-being. Reliable development analysis pairs an income measure with a composite measure such as HDI.