Introduction

Hi, I’m Jonathan Mitchell, IELTS Writing examiner and academic English trainer.
In Academic Writing Task 1, strong data vocabulary separates a Band 6.5 script from a Band 8 or 9. The way you describe numbers, percentages, proportions, and changes shows your ability to use precise and varied academic language.

In this guide, we’ll explore how to describe data clearly, avoid repetition, and use correct structures to communicate trends, comparisons, and quantities naturally.

Why Data Vocabulary Matters

Under Lexical Resource, examiners assess your range, accuracy, and appropriacy of vocabulary.
Repeating basic words like increase and decrease limits your band score. Instead, you should demonstrate variety and precision — using different word forms and accurate collocations.

For example:
❌ The number increased a lot.
✅ The figure rose sharply by 25% over the decade.

That single sentence shows a richer command of English and improves your lexical score immediately.

Vocabulary for Quantities and Proportions

Meaning	Useful Vocabulary	Example Sentence
Large amount	majority, bulk, vast number, a large proportion	The majority of students preferred online learning.
Small amount	minority, small fraction, slight proportion	Only a small fraction of residents used public transport.
Half or equal	half, one in two, equally, the same proportion	Half of the respondents were in favour of the proposal.
Three-quarters / one-third	a quarter, a third, three-quarters	Nearly three-quarters of the population owned smartphones.

Band 8 Tip: Use approximately, around, or just over to make your data description sound natural.

Approximately 60% of households had Internet access.

Vocabulary for Percentages and Ratios

Expression Type	Examples
Exact percentages	10%, 25%, 40% — Twenty-five percent of respondents…
Approximate values	around 50%, nearly one-third, roughly 10%
Comparisons	twice as much as, three times higher than, half as many as

Example:

In 2020, the proportion of female graduates was nearly twice as high as that of males.

Vocabulary for Trends and Changes

Avoid overusing “increase” and “decrease.” Rotate between different verbs and nouns for variety.

Trend Type	Verbs	Nouns
Increase	rise, climb, grow, go up, soar, surge	a rise, an increase, a growth, an upward trend
Decrease	fall, drop, decline, go down, plummet, diminish	a fall, a decline, a reduction, a downward trend
No change	remain stable, stay constant, maintain	stability, no significant change
Fluctuation	vary, oscillate, shift	fluctuation, variation, inconsistency

Example:

Exports rose gradually during the first half of the period but fell sharply afterwards.

Adverbs and Adjectives for Describing Degree

Using descriptive adverbs and adjectives makes your report sound precise and academic.

Degree	Adverbs / Adjectives	Example
Large	dramatically, significantly, substantially, sharply	Sales increased significantly* in 2020.*
Moderate	steadily, gradually, moderately, consistently	The rate grew gradually* over the decade.*
Small	slightly, marginally, minimally	The figure declined slightly* after 2015.*
Sudden	rapidly, abruptly, quickly	Tourism numbers rose rapidly* following 2018.*

Band 8 Tip: Combine adverbs and verbs correctly: rose dramatically, fell slightly, remained relatively stable.

Vocabulary for Extremes and Comparisons

Purpose	Examples
Highest / Lowest	the highest, the lowest, the peak, the bottom point
Equality	equally, similarly, almost the same
Contrast	whereas, while, in contrast to, compared with
Superlatives	the most significant, the least common, the greatest number

Example:

Germany recorded the highest level of renewable energy use, whereas Japan’s figure remained the lowest.

Vocabulary for Describing Averages and Totals

Function	Examples
Mean / Average	the mean, the average figure, on average
Total / Overall	total amount, combined total, in total
Proportionate statements	accounted for, represented, constituted

Example:

In 2020, renewable sources accounted for nearly 30% of total electricity production.

Vocabulary for Describing Time and Frequency

Expression Type	Examples
Time phrases	over the period, between 2000 and 2020, throughout the decade
Frequency	frequently, rarely, occasionally
Sequence indicators	initially, subsequently, eventually, thereafter

Example:

Initially, Internet usage was low, but it increased rapidly thereafter.

Formal and Academic Substitutions

Avoid using everyday vocabulary in formal descriptions.

Informal / Basic	Formal Alternative
a lot of	a large number of / a significant proportion of
very big	substantial / considerable
very small	minimal / marginal
go up	increase / rise / grow
go down	decrease / decline / fall
show	illustrate / depict / represent

Band 8 Tip: Examiners look for formal precision, not creative expression. Avoid idioms and conversational tone.

Collocations for IELTS Task 1

Collocation Type	Examples
Trend Collocations	experience growth, witness a decline, remain unchanged
Comparison Collocations	show a contrast, demonstrate a difference, display similarity
Quantity Collocations	a large proportion, a slight majority, a considerable number
Time Collocations	over the next decade, in the following years, throughout the period

Example:

The country witnessed a steady rise in exports over the following years.

Common Mistakes with Data Vocabulary

Mistake	Explanation	Correction
Using informal words	Reduces academic tone	Replace a lot with a large proportion
Mixing up “by” and “to”	Alters meaning	Increased by 10% → final value rose to 60%
Repeating “increase/decrease”	Repetitive language	Use rise, fall, drop, climb, decline
Adding explanations (“because”)	Task 1 doesn’t require reasons	Focus only on describing data
Using incorrect quantifiers	Many information ❌	Much information / many figures ✅

Mini Practice

Task: Rewrite this sentence using precise data vocabulary.

The number of tourists went up a lot after 2015.

✅ Answer:

The number of tourists increased significantly after 2015.

Now try improving:

There was a small drop in car sales. → Car sales declined slightly during the same period.

Quick Self-Check

Before finishing your report, ask yourself:

Did I use at least five varied data verbs and nouns?
Are my adverbs and prepositions accurate?
Did I avoid repetition and informal words?
Is my vocabulary formal and precise throughout?

If yes, you’re already producing Band 7+ lexical performance.

Summary & Next Steps

Effective Data Vocabulary for Academic Task 1 helps you describe complex visuals clearly and confidently.
Focus on variety, precision, and collocation rather than memorising long word lists.

Next, move on to Model Answers & Analysis to see these vocabulary techniques in action across real Band 8–9 samples.
You can also return to the IELTS Writing Overview: Format, Scoring & Key Skills for a complete foundation, or visit IELTS.org for authentic sample tasks.