IELTS vocabulary: Population and Demographics

Population and demographics appear regularly as a Task 1 topic whenever a chart tracks age structure or population size over time, and as a Task 2 topic when an essay discusses the causes or consequences of an ageing population, migration, or urbanisation. The failure mode specific to this topic is describing the shape of the change — "there are more old people and fewer young people" — without naming the mechanisms driving it or the specific systems it puts under strain, both of which have precise, usable vocabulary that most candidates never reach for.

Vocabulary for change over time is the foundation of any Task 1 description on this topic and remains useful in Task 2 as well. "Population growth" versus "population decline" describes the overall direction of change, while "demographic shift" is the broader term for any significant change in a population's structure, not only its size. "Birth rate" and "death rate" (usually expressed per thousand people per year) are the basic building blocks, while "fertility rate" is a more specific, technical measure — the average number of children a woman is expected to have in her lifetime — worth using instead of birth rate when an essay wants precision about reproductive patterns specifically rather than raw birth counts. "Life expectancy" (the average number of years a person is expected to live) is the counterpart statistic on the other side of the same trend.

Age-structure vocabulary lets an essay describe a population's composition rather than only its size. "Ageing population" refers to a population with a growing proportion of older people, usually resulting from the combination of falling fertility and rising life expectancy described above. "Working-age population" (typically defined as adults between roughly 15 and 64) is the group whose size relative to dependents matters enormously for economic essays. "Dependency ratio" is the precise, technical term for the ratio of dependents — children and the elderly — to the working-age population, and is considerably more specific and impressive than saying there are "more old people to look after." "Population pyramid" is the standard visual and conceptual term for representing a population's age structure, useful for essays or Task 1 responses discussing how a country's shape has changed from a traditional pyramid to a more rectangular or even inverted structure. "Median age" (the age at which exactly half a population is older and half younger) is a single, easily compared figure worth using alongside a population pyramid when a Task 1 answer needs to summarise the overall shift in one number rather than describing the full distribution.

Causal vocabulary lets an essay explain why a demographic shift is happening, rather than only describing that it is. "Improved healthcare" and "medical advances" are the standard, broad explanations for rising life expectancy. "Delayed parenthood" (people having children later in life, or not at all) is a specific, citable cause of falling fertility rates, often linked to "urbanisation" (population movement into cities), which is itself frequently associated with declining birth rates due to higher living costs and different social patterns in urban areas. "Family planning" refers to the deliberate choice and ability to control the number and timing of children, relevant both to falling birth rates in some countries and to policy debates in others. "Rural-to-urban migration" is a more specific phrase than urbanisation alone, useful when an essay wants to name the actual movement of people rather than only its demographic effect.