A population pyramid shows the share of a population in each age group, with males on one side and females on the other. Read it in three passes: the base, the middle and the top.
This lesson belongs to population growth, structure and migration. The figures behind the shape come from separating natural change from net migration.
What does each part of the pyramid tell you?
The base shows children and so points to recent births. The middle shows working-age adults. The top shows older people and how long people live.
Always read the axis first. Check whether bars show a count or a percentage of the whole population.
Worked example: Town Sinar
This is an original pyramid for a town, in percent of the total population. Each row gives male and female shares.
| Age group | Male % | Female % |
|---|---|---|
| 60 and over | 6 | 9 |
| 45 to 59 | 8 | 10 |
| 30 to 44 | 13 | 13 |
| 15 to 29 | 12 | 12 |
| 0 to 14 | 9 | 8 |
Check: males add to 9 + 12 + 13 + 8 + 6 = 48, females to 8 + 12 + 13 + 10 + 9 = 52, total 100.
- Base. Children (0 to 14) are 17% of the town, less than the 15 to 29 group at 24%, which suggests fewer births in the last fifteen years.
- Middle. The 30 to 44 group is widest at 26%, so working-age adults dominate.
- Top. Women aged 60 and over are 9% and men 6%, which suggests women live longer here.
The mistake that costs marks
The common slip is to read bar length as a head count, or to state a cause the shape cannot prove.
- Wrong: “Men aged 60 and over are 6, so there are only 6 older men.”
- Right: “Men aged 60 and over make up 6% of the population.”
- Wrong: “The bulge at 30 to 44 proves a lot of workers moved here.”
- Right: “The bulge at 30 to 44 suggests a large working-age group, which may include in-migrants.”
Check yourself
In a village pyramid, the 0 to 14 bars are 7% male and 7% female. The 15 to 29 bars are 10% male and 10% female. What does this suggest, and what extra data would you want?
Answer
There are fewer children (14%) than young adults (20%), which suggests that births fell over the last fifteen years. It does not prove why.
Extra data would be annual births and deaths, and migration figures, to check whether young people also moved away.
What to study next
Comparing two pyramids fairly needs the same age categories in both. Continue with comparing age structures using the same category definitions, then test yourself on the growth and migration practice set.
If you want a teacher to go through a pyramid with you, see online one-to-one Geography tuition.