Another way to examine population is by using a population pyramid. A population pyramid is a kind of bar graph. Each horizontal bar shows how many males or females fall into a specific age group. This is called an “age-gender” cohort. The bars are stacked one on top of another in ascending order with the youngest group on the bottom and the oldest on top. A center line divides the graph into a female and male side.

Source: Population Pyramids of Texas, U.S. Census Bureau.

Take a look at the population pyramids of Texas. What is the connection between the age and sex structure of a population? Why does this matter? The age-sex structure determines the potential for growth of specific age groups and the total population. Therefore, an understanding of a population age structure is critical for informed decision-making.

 The shape of the pyramid indicates the potential for future growth and can also provide hints about past trends.

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Click here for a couple of hints to help you analyze a population pyramid.

Helpful Hints: A top-heavy pyramid suggests negative population growth that might be because of any number of factors, including high death rates, low birthrates, and increased immigration. A bottom-heavy pyramid suggests high birth rates, falling or stable death rates, and the potential for rapid population growth.

Reading a population pyramid can be difficult, but click different areas on the pyramid below to learn the important parts of a population pyramid.

Now that you know what a population pyramid is and how it works, let’s look at what a population pyramid can tell us. (Click the correct letter to check your answer)

Activity:

1. Which of the following statements can be supported by the population pyramid above?

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A. The largest age group of females in the United States is 45-50.

Correct! There are about 12 million females aged 40-45 based on the population pyramid.

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B. This pyramid is top-heavy, indicating a negative population growth. Incorrect. The opposite is true for this pyramid. It is bottom-heavy which indicates that there is rapid population growth.

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C. There are more older males than younger males in the United States. Incorrect. The opposite is true. There are more younger males than older males based on this pyramid.