Measuring Development: GNI, HDI & the DTM
Why Measure Development?
Development is uneven across the planet — some countries are very rich, with long lives and good schools, while others struggle with poverty and disease. Geographers measure development so that aid can be targeted, governments can compare progress, and patterns of inequality become visible. The challenge is that no single number captures everything that matters about a country’s quality of life.
Development is measured using two types of indicator: economic measures (GNI per head, employment) and social measures (life expectancy, literacy, infant mortality). HDI combines both into one score from 0 to 1.
Economic Indicators
The most common economic measure is Gross National Income (GNI) per head. It adds up everything a country’s citizens and businesses earn, including overseas income, and divides by population. Norway’s GNI per head is around US$95,000; Burundi’s is around US$240. The gap is enormous. Economists also track unemployment rates and the share of workers in primary, secondary, tertiary and quaternary industries — richer countries tend to have far more service-sector jobs.
Social Indicators
Social indicators measure quality of life. Infant mortality is one of the most sensitive: in the UK around 4 babies in 1,000 die before their first birthday, while in Sierra Leone the figure is over 70. Life expectancy ranges from 84 years in Japan to under 55 in some sub-Saharan African countries. Literacy rates measure education access, and the number of people per doctor shows healthcare provision — the UK has roughly 3 doctors per 1,000 people; Malawi has fewer than 0.05. Access to safe water completes the picture: where less than 60% of people have clean water, child deaths from diarrhoea soar.
Every single indicator has weaknesses. GNI per head is an average — it hides huge inequality. A country can have an oil-rich elite and a poor majority, yet still record high GNI. Data may be old, missing or unreliable, especially in poorer countries. Some economic activity goes unrecorded in the informal economy — an estimated 70% of African workers earn this way. Social indicators have their own issues: literacy may be self-reported, and life expectancy averages mask whether men or women, rich or poor, live longer.
The Human Development Index
To overcome the weaknesses of single measures, the United Nations created the Human Development Index (HDI). It blends three dimensions: a long, healthy life (life expectancy), knowledge (mean and expected years of schooling) and a decent standard of living (GNI per head). Each country gets a score between 0 and 1. Norway and Switzerland sit above 0.95, the UK around 0.93, India around 0.64, and Niger near 0.40. HDI is more useful than GNI alone because it shows whether wealth is being turned into education and health.
HDI combines life expectancy, education (years of schooling) and GNI per head. Scores run from 0 to 1: UK around 0.93, India around 0.64, Niger around 0.40.
The Demographic Transition Model
The Demographic Transition Model (DTM) links population change to development. As a country develops, both birth and death rates fall, but at different times. The gap between them shapes population growth.
Stage 1 — High fluctuating: birth and death rates both high, population stable. Now found only in remote tribal communities.
Stage 2 — Early expanding: death rate falls due to better food, water and medicine, but birth rate stays high. Population grows fast. Examples: Afghanistan, parts of sub-Saharan Africa.
Stage 3 — Late expanding: birth rate falls as women gain education, contraception spreads and child labour becomes less needed. Population still grows but more slowly. Examples: India, Brazil.
Stage 4 — Low fluctuating: both rates low, population steady. Examples: UK, USA, Australia.
Stage 5 — Decline: birth rate falls below death rate, so population shrinks and ages. Examples: Japan, Germany, Italy.
Linking the DTM to Development
The DTM lines up neatly with the development indicators. Stage 2 countries usually have low GNI, high infant mortality and HDI below 0.55. Stage 3 countries are the classic NEEs — rapid growth, falling birth rates, HDI rising past 0.65. Stage 4 countries are HICs with high GNI and HDI above 0.85. Stage 5 introduces a new problem: an ageing population means fewer workers supporting many pensioners. The DTM is not perfect — it was based on European history and assumes every country follows the same path — but it is a powerful way of linking population change to development.