ENGLISH · LESSON 11 OF 20
Describe a chart with an overview and accurate comparisons
What this lesson helps you do
Select the main pattern in a simple dataset and explain changes without inventing causes.
Before this lesson
This lesson builds on:
The explanation
Begin by identifying what is measured, the units, the groups and the time period. An overview describes the most important pattern across the data. Supporting paragraphs then give selected values and comparisons. An overview is not a list of every number, and a data description is not an explanation of causes unless the supplied information supports them.
Percentage points and percentage change answer different questions. A rise from 40% to 55% is an increase of 15 percentage points. Relative to the starting share, the increase is 15 divided by 40, or 37.5%. State which measure you mean. Use approximate language only when appropriate to the precision shown.
For IELTS Academic Writing Task 1, current official guidance requires at least 150 words. The complete model below is an original example using invented data; it has not been scored by an IELTS examiner. The principle also applies to university reports, where the assignment may have different length and formatting requirements.
| Year | Bus (%) | Walking (%) | Car (%) |
|---|---|---|---|
| 2015 | 40 | 20 | 40 |
| 2020 | 50 | 25 | 25 |
| 2025 | 55 | 30 | 15 |
Invented educational data; not a real survey.
Language pattern
- Pattern
- Introduction to data → overview → selected comparisons with units.
- What it does
- Lead with the pattern, then show the evidence.
- Limits
- The dataset describes reported travel mode, not causes, journey frequency or environmental effects.
A first worked example
A complete original data description
Situation. Invented campus survey: main travel mode (%). 2015: bus 40, walking 20, car 40. 2020: bus 50, walking 25, car 25. 2025: bus 55, walking 30, car 15. Each annual sample contains 1,000 respondents and each row totals 100%.
The table compares the percentages of respondents who reported travelling mainly by bus, on foot or by car in three campus surveys conducted in 2015, 2020 and 2025. Each survey included 1,000 respondents.
Overall, bus use and walking became more common, while the proportion travelling mainly by car fell. Bus travel was the largest category in the final two surveys, and by 2025 it accounted for more than half of the responses.
In 2015, buses and cars each represented 40% of the sample, whereas walking accounted for the remaining 20%. Five years later, the bus share had risen to 50%. Walking and car travel were then equal at 25% each.
By 2025, the proportion reporting bus travel had reached 55%, and walking had increased to 30%. Car travel, in contrast, had declined to 15%, a fall of 25 percentage points from its initial level. Across the full period, the increase in walking was steady, at five percentage points between each pair of surveys, while the growth in bus use slowed in the second interval.
Why it works
- The introduction identifies the measure and dates.
- The overview names the main directions without inventing reasons.
- The detail paragraphs select useful comparisons and retain percentage units.
- The ending compares changes across intervals; it does not add an unsupported opinion.
What it shows: A complete description can be organised and selective while remaining faithful to every stated number.
A second worked example
Distinguish two ways to describe a change
Situation. The bus share rises from 40% to 55%.
The bus share increased by 15 percentage points, equivalent to a 37.5% increase relative to its original share.
Why it works
- 55 minus 40 gives 15 percentage points.
- 15 divided by 40, multiplied by 100, gives the relative percentage change.
- Neither value is a claim that the number of bus journeys rose by that amount.
What it shows: Name the denominator and the quantity being compared.
Common mistakes
Draft (not correct): The bus share increased by 15%.
Revision: The bus share increased by 15 percentage points.
The first wording confuses a difference between percentages with a relative change.
Draft (not correct): The survey proves that cheaper tickets caused the increase.
Revision: The survey shows an increase in the reported bus share.
Ticket prices and causation are not given in the dataset.
Keep in mind
- Identify the unit before describing change.
- Give an overview before selected details.
- Do not invent a cause to make a description sound complete.
Foundation lesson; not an official syllabus, accredited CEFR placement, or score prediction.
Next: Explain a process and report completed work. Describe a sequence accurately, with clear units and a deliberate choice of time and voice.
Original Bayt Al-Fuad teaching text and invented examples; not publisher lesson text. Aligned with: The Official Cambridge Guide to IELTS: published contents, ISBN 9781107620698 · IELTS Academic: Writing test format · University Success level differentiation. Sources and credits.