Many Geography questions supply a graph or table of how income is divided between groups and ask you to interpret it. The skill is to turn the picture into figures, make one comparison and note a limit. It follows explaining a mechanism in development and inequality.
The data below are invented. You can practise reading shares and averages with the statistics and distribution explorer.
How do you interpret a graph step by step?
- Read the title, the axes and the units. Are the bars shares of income, in per cent, for groups of equal size?
- Describe the overall pattern. Do shares rise steeply from the lowest group to the highest?
- Quote figures. Give the lowest and highest groups with units.
- Make a comparison. Divide the highest share by the bottom share, or subtract.
- Compare with equality. With five equal groups, equal sharing means 20 per cent each.
- State a limit. Say what the data do not show.
Worked example
Invented income shares by fifth of households in Country M:
| Group (fifths, lowest to highest) | Share of income (%) | Cumulative share (%) |
|---|---|---|
| Bottom 20% | 5 | 5 |
| Second 20% | 10 | 15 |
| Middle 20% | 15 | 30 |
| Fourth 20% | 22 | 52 |
| Highest 20% | 48 | 100 |
Check the total: 5 + 10 + 15 + 22 + 48 = 100. Good.
Ratio: 48 ÷ 5 = 9.6. The highest fifth receives 9.6 times the share of the bottom fifth.
Cumulative reading: the bottom 60 per cent of households receive 30 per cent of income. Check: 5 + 10 + 15 = 30.
Written interpretation: “Income in Country M is unevenly shared. The highest 20 per cent of households receive 48 per cent of income, compared with 5 per cent for the bottom 20 per cent, a ratio of 9.6 to 1. Under equal sharing each fifth would receive 20 per cent. The data show shares only, so they do not tell us how much income there is in total.”
What mistake should you watch for?
Mistaken answer: “The bottom 60 per cent receive 15 per cent of income.”
The student took the 15 per cent from the cumulative column at the second group, which covers only the bottom 40 per cent. The bottom 60 per cent is the third row, 30 per cent.
The correction is to check how many groups the question refers to, then match the row. When you use a cumulative column, say “the bottom X per cent receive Y per cent in total”. When you use the share column, say “this group receives”.
Check yourself
All data are invented.
1. Shares by fifth in Country N are 8, 12, 16, 24 and 40 per cent. How many times larger is the highest share than the bottom share?
Show answer
40 ÷ 8 = 5 times. Check the total: 8 + 12 + 16 + 24 + 40 = 100.
2. What share of income goes to the bottom 40 per cent in Country N?
Show answer
8 + 12 = 20 per cent.
3. A student says Country N is more equal than Country M. Is this supported by the data, and what is one limit?
Show answer
On this measure, yes: the highest-to-lowest ratio is 5 compared with 9.6, and the bottom 40 per cent receive 20 per cent compared with 15 per cent in Country M. The limit is that the data show shares only, and may be from different years.
Where does this lead next?
Next, learn what a graph can and cannot prove in separating a causal claim from a correlation. The map scale, contour and gradient practice tool helps with other supplied data skills such as reading figures from a diagram. To practise writing interpretations with someone checking each sentence, see online one-to-one Geography tuition.