Teacher's Guide: Discussion Questions

Three Patterns of Population Change

Source: United Nations, World Population Prospects, The 2006 Revision.

  1. What percentage of the population of the Democratic Republic of Congo, the United States, and Germany are 0–4 years old?
    Which of the three countries has the greatest proportion of people ages 65 and older?


  1. How can the age-sex structure of a population help determine the needs of that population?
  2. What does it mean to have a "young" or "old" population?
  3. How can migration affect the shape of a pyramid?
  4. What is "zero population growth"? Which pyramid represents this concept?


The dependency ratio is a measure used to indicate the ratio of people in the "dependent" ages (under 15 and ages 65 and older) per 100 people in the "economically productive" ages (15–64 years of age). The formula for the dependency ratio is:

The age dependency ratio for the United States is shown below at 49.

This means that there were 49 people in the dependent ages for every 100 persons in the working ages.

  1. Calculate the dependency ratios for Kenya, Germany, Brazil, and Japan. Compare the components of each of them.


Discuss the implications of high or low dependency ratios for economic resources and development.