Study guides & original practice
Demographic transition model practice
The demographic transition model describes broad changes in birth and death rates during demographic change. Use it as an interpretive model, not a schedule every country must follow identically.
By ExamCat · Original study lesson · Published September 24, 2026
Understand the method
Population growth is influenced by the gap between birth and death rates, with migration adding another component. Falling mortality can increase natural growth before fertility falls. Even lower fertility does not instantly erase the effects of a young age structure.
Worked example, step by step
In an invented country, the crude death rate falls from 30 to 10 per thousand while the crude birth rate remains 35 per thousand.
- Initially, the natural-increase rate is 35 − 30 = 5 per thousand.
- After the mortality decline, the gap is 35 − 10 = 25 per thousand.
- That is 2.5% natural increase using the stated crude-rate approximation.
- This pattern is consistent with an early mortality decline in the model; it does not identify every social condition in the country.
A mistake to watch for
A stage label is not an explanation by itself. State which rate changed and how that alters the gap. Migration, policy, conflict and other events may complicate the stylized pattern.
Try it yourself: three questions
Write an answer before opening the explanation. For calculations, keep your units and intermediate steps; for concepts, state the reason for your choice.
1. Birth and death rates are both low and close together. What does that suggest about natural increase?
Show answer and explanation
It is low. Total growth could still differ if migration is substantial.
2. Why can population keep increasing after fertility declines?
Show answer and explanation
A large cohort entering reproductive ages can generate many births even with fewer births per person. Age structure matters.
3. Does falling death rate mean nobody dies?
Show answer and explanation
No. It means deaths relative to the population are lower under the measure; absolute deaths can behave differently as population size and age structure change.
Build your next practice session
Mark the first step where your reasoning differed from the explanation. Turn that step into a question, answer it without looking, then change one condition in the example and explain what would change. A correct guess is a reason to revisit the method.
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Further reading
AP Human Geography course overview provides textbook background. The worked scenario and practice questions on this page were written independently for ExamCat.
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