Dependency Ratio in AP Human Geography

Counting by age, not by who has a job

The dependency ratio sorts people by birthday only. A 70-year-old still running a company counts as a dependent, and a 30-year-old who can't find work counts as working-age. That's the main thing separating it from the unemployment rate, which measures actual joblessness among people in the labor force. When an answer choice treats dependency ratio as an employment statistic, it's wrong.

Here's a worked example you can do without a calculator (the exam doesn't allow one). Say a country has 30 million people under 15, 10 million over 64, and 50 million ages 15-64. Dependents total 40 million, and 40 ÷ 50 = 0.8, or 80 dependents per 100 working-age people. Some questions write it as a decimal (0.8) and others as a whole number (80). They mean the same thing.

Same ratio, opposite pyramids: youth vs. aged dependency

Geographers split the ratio in two because the halves have different causes. In the example above, the youth dependency ratio is 30 ÷ 50 × 100 = 60, and the aged (old-age) dependency ratio is 10 ÷ 50 × 100 = 20. That country's load comes mostly from children.

A country with high birth rates, usually in the early stages of the demographic transition model (Topic 2.5), has a wide-based population pyramid and high youth dependency. A country with low fertility and long life expectancy has a top-heavy pyramid and high aged dependency. Two countries can post the same overall ratio for opposite reasons, so a high ratio does not automatically mean an aging population. Check which end of the pyramid is wide before you explain anything.

This is also why reading pyramids in Topic 2.3 (Population Composition) matters. Pyramids help forecast future demand for goods and services, and the dependency split tells you whether that demand leans toward schools and maternity care or toward nursing homes and pensions.

What a rising aged dependency ratio does to a country

The dependency ratio is named directly in Topic 2.9 (Aging Populations) in Unit 2: Population and Migration, as one of the economic, social, and political effects of a population growing older. The course frames it as a consequence. Population aging is driven especially by lower birth rates and longer survival into older ages, and those changes can raise the aged dependency ratio. Keep cause and effect in the right order when you explain it.

Japan is the standard example, with a shrinking population and more than 28 percent of people aged 65 or older. Consequences you can name include:

• fewer workers paying taxes that fund pensions and health care
• labor shortages in sectors like elder care and manufacturing
• political pressure to raise the retirement age or cut benefits
• more spending on health care and less on schools

Those pressures connect to Topic 2.7 (Population Policies). Governments facing a high aged dependency ratio often turn to pronatalist policies (paying or supporting families to have more children) or to immigration policies that bring in working-age adults. Immigration lowers the ratio faster, since new workers arrive as adults, while new babies count as dependents for 15 years first.

Reading the ratio from a data table or across scales

Say a data table lists two countries with nearly the same dependency ratio, plus each one's birth rate, life expectancy, and median age. The question asks which country's load is youthful and which is aged, or what caused the aging, and that same comparison can show up as a population pyramid instead. A country with a low birth rate, high life expectancy, and high median age is the aging one, even if a young, high-fertility country has a similar or lower overall ratio.

On the free-response section, it fits Question 2 (One-stimulus question) or Question 3 (Two-stimuli question) when the stimulus is a pyramid or population data. A strong answer does three things: identifies whether the dependency is youth or aged, ties it to a cause (fertility, mortality, or migration), and explains one specific economic or political consequence.

Scale matters too, since free-response questions can ask for analysis across scales. A national ratio can hide big differences inside a country. When working-age adults migrate from rural areas to cities, they leave children and older people behind, so rural dependency ratios rise while city ratios fall. That links back to Topic 2.2 (Consequences of Population Distribution): rural areas with high dependency and fewer workers have a harder time paying for services such as medical care.