The Demographic Transition Model Explained
The demographic transition model (DTM) describes how a country’s birth rates, death rates and population growth change over time as it develops, usually in four or five stages, from high birth and death rates to low birth and death rates. In brief: in Stage 1 both rates are high and the population is stable; in Stage 2 death rates fall while birth rates stay high, causing rapid growth; in Stage 3 birth rates fall and growth slows; in Stage 4 both rates are low and the population is stable; in Stage 5 (in some versions) births fall below deaths and the population declines.
The model was built from the experience of Europe and is widely used to compare countries and explain population change. This guide explains each stage, why the rates change, what the model leaves out, compares the stages in a table, works through examples, outlines how the idea developed and corrects common mistakes.
What is the demographic transition model?
The model is a graph with time on the horizontal axis and the birth rate and death rate on the vertical axis (per 1,000 people). The population change is shown by the gap between the two lines: when the birth rate is above the death rate, the population grows, and the larger the gap, the faster the growth. A third line or shaded area often shows the total population, which follows an S-shaped (sigmoid) curve over the stages.
What happens in each stage?
Stage 1: High stationary
Birth rates are high, often 35 to 50 per 1,000, but death rates are also high because of disease, famine and poor hygiene. Natural change is close to zero and fluctuates with epidemics and bad harvests. The population is very young. Few countries are in this stage today, and it is mostly seen in isolated groups.
Stage 2: Early expanding
Death rates fall rapidly thanks to better food supply, clean water, sanitation, vaccination and medicine, but birth rates remain high because attitudes and customs change slowly and children are still seen as economically useful. The gap widens, and population grows quickly. Infant mortality falls, so more children survive. Several countries in sub-Saharan Africa are near this stage.
Stage 3: Late expanding
Birth rates begin to fall as incomes rise, women gain education and jobs, contraception is available, more people live in cities and child survival is high. Death rates continue to fall slowly. The population still grows, but at a decreasing rate. Many middle-income countries, such as parts of Latin America and South Asia, are in or near this stage.
Stage 4: Low stationary
Birth and death rates are both low, often around 10 to 15 per 1,000 for births and 8 to 12 for deaths, so the population is stable or growing slowly. Fertility is close to or below replacement level. Birth rates may fluctuate with economic conditions. Most high-income countries were in this stage for a long time.
Stage 5: Declining (in some versions)
Birth rates fall below death rates, and the population decreases unless immigration compensates. The population is old, and the proportion of working-age people falls. Japan and several European countries are examples. It is debated whether a fifth stage is part of the model or just an extension of Stage 4.
Why do birth and death rates change?
Death rates fall first because the causes are largely technical: improved medicine, hygiene, water supply and farming can be adopted quickly, sometimes imported from abroad. Birth rates fall later because they depend on social change: education, women’s roles, urbanization, costs of raising children, the availability of family planning and expectations about security in old age. The delay between the two falls produces the population boom of Stage 2 and 3.
What are the limits of the model?
- It is based on the history of Western Europe, and other countries may follow different paths and speeds. Some countries have moved through the stages in just a few decades.
- It ignores migration, which can change a country’s population strongly.
- It does not account for government policies, such as China’s one-child policy, or for events such as war and pandemics (HIV/AIDS raised death rates in parts of Africa).
- It assumes that all countries will end up in Stage 4, though future fertility may fall further than expected.
- It treats countries as separate units and ignores global links such as aid and technology transfer.
The stages compared
| Stage | Birth rate | Death rate | Natural change | Population |
|---|---|---|---|---|
| 1: High stationary | High | High | Near zero | Stable, small |
| 2: Early expanding | High | Falling fast | Rapid increase | Growing quickly |
| 3: Late expanding | Falling | Low, falling slowly | Slowing increase | Growing more slowly |
| 4: Low stationary | Low | Low | Near zero | Stable, large |
| 5: Declining | Very low | Low or rising | Negative | Shrinking |
Worked example: reading the model
- Stage from data: a country has a birth rate of 40 and a death rate of 12 per 1,000. Natural change is 40 − 12 = 28 per 1,000, or 2.8% per year. A high birth rate with a low death rate indicates Stage 2.
- Another country: birth rate 18, death rate 7: natural change = 11 per 1,000 = 1.1%. The birth rate has fallen but still exceeds the death rate, which suggests Stage 3.
- Stage 4 check: birth rate 11, death rate 9: change = 2 per 1,000 = 0.2%, nearly stable, which fits Stage 4.
- Stage 5 check: birth rate 7, death rate 12: change = −5 per 1,000 = −0.5%, a population in natural decline, as in Stage 5.
- Growth in Stage 2: a population of 10 million at 2.8% growth gains about 280,000 people in the first year. After 25 years at a constant 2.8% it multiplies by 1.02825 = about 2.0, so it roughly doubles, in line with the rule of 70 (70 ÷ 2.8 = 25 years).
How did the model develop?
The American demographer Warren Thompson described the pattern of falling death and birth rates in 1929, and Frank Notestein developed the theory in the 1940s. The model grew from observations of Europe and North America in the 19th and early 20th centuries, where industrialization, medicine and urbanization changed population growth. After 1945, death rates fell very quickly in many developing countries as imported medicine and public health programs spread, causing faster growth than in Europe in the past. Later authors added a fifth stage to account for very low fertility.
Which mistakes are common?
Mistake 1: Thinking that the population stops growing in Stage 3
Growth slows in Stage 3 but continues, because the birth rate is still above the death rate.
Mistake 2: Saying that the birth rate falls first
The death rate falls first. The delay before birth rates fall creates the population boom.
Mistake 3: Assuming that all countries follow the same timetable
The pace and timing differ widely, and policy, culture, disease and migration can change the path.
Mistake 4: Treating the model as a prediction
The model is a generalization from past experience that helps in comparing countries. It does not guarantee how a particular country will develop.