A demographic graph describes numbers in age bands for an area. You can state what the numbers show and suggest causes the evidence supports. You cannot claim what all people in a group are like.
This lesson is part of population and settlements. It builds on explaining migration push and pull factors, because migration changes an area’s age structure.
What can a graph tell you?
It can tell you the size of each age band, which bands are largest, and how the structure compares with another area. From these you can work out measures such as the dependency ratio.
It cannot tell you individual behaviour, opinions or abilities.
Worked example: a dependency ratio on invented figures
Town X is an invented town with these age bands (counts in the graph key).
| Age band | Number |
|---|---|
| Under 15 | 240 |
| 15 to 64 | 640 |
| 65 and over | 120 |
Check the total: 240 + 640 + 120 = 1 000.
Dependants are 240 + 120 = 360. Dependency ratio = 360 ÷ 640 × 100 = 56.25, which rounds to 56.3. Read it as dependants per hundred workers.
Turning the number into a fair conclusion
A good sentence: “Town X has a dependency ratio of 56.3, so the young and older bands together are just over half the size of the working-age band. The younger band is larger than the older band, which suggests a recent history of births or families moving in.”
The wording describes the area and gives a cautious cause. It does not say anything about what young or older people are like.
The mistake that costs marks
The slip is a sweeping claim, such as “older people do not contribute to the economy”. The graph has no data on contribution, and the sentence judges a whole group.
| Stereotyping | Fair |
|---|---|
| “Older people are a burden.” | “The 65 and over band is 120, which raises the dependency ratio and increases demand for health services.” |
| “Young people are not productive.” | “The under 15 band is 240, so the area needs schools and will add working-age adults in the future.” |
Check yourself
Town Y has 180 under 15, 700 aged 15 to 64 and 120 aged 65 and over. Calculate the dependency ratio and compare it with Town X.
Answer
Dependants: 180 + 120 = 300. Ratio: 300 ÷ 700 × 100 = 42.857, so 42.9.
Town Y has a lower ratio than Town X (42.9 against 56.3), so the working-age band supports fewer dependants. The difference comes mainly from its smaller young band, and the graph alone cannot say why.
What to study next
Try the population and settlements practice set. The graph evidence and fair-comparison lab lets you practise cautious, evidence-first wording.
If you want a teacher to check that your conclusions stay inside the data, see online one-to-one Geography tuition.