Common Grammar Mistakes in IELTS Writing Task 1: How to Avoid Them

IELTS Writing Task 1 demands accuracy. You're describing data, processes, or maps under strict time pressure, and grammar errors stack up fast. The difference between Band 6 and Band 7 often comes down to accuracy, not vocabulary or ideas. This post covers the eight mistakes that appear in roughly 70% of Band 6 essays—and how to eliminate them.

1. Subject-Verb Agreement With Plural Subjects

This mistake appears more often than you'd expect, especially when a noun phrase separates the subject from the verb.

Wrong: "The number of tourists visiting the city have increased significantly."

Right: "The number of tourists visiting the city has increased significantly."

The subject is "number" (singular), not "tourists." The phrase "of tourists" is just a prepositional modifier. Similarly:

"A series of events" takes "has", not "have"
"The majority of people" takes "have" (because the focus is the plural noun)
"A group of students" takes "has" (when referring to the group as a unit)

Read the sentence and identify the actual subject first. Cross out the middle phrase mentally: "The number [of tourists] have increased" becomes obviously wrong.

2. Tense Inconsistency Within Paragraphs

Task 1 often shows past data alongside present or projected trends. Switching tenses without reason confuses readers and signals careless writing.

Wrong: "In 2010, the UK exported 45 million tonnes. By 2015, exports increased to 67 million tonnes, and in 2020, they are at 72 million tonnes."

Right: "In 2010, the UK exported 45 million tonnes. By 2015, exports had increased to 67 million tonnes, and in 2020, they reached 72 million tonnes."

All three events are in the past, so use past simple or past perfect consistently. If you're describing a current trend based on historical data:

"The data shows that exports rose steadily from 2010 to 2020." (Simple present for the observation; past tense for the data itself.)

3. Missing or Incorrect Articles

Articles (a, an, the) cause trouble especially with countable nouns and when moving between specific and general references.

Wrong: "Graph shows increase in unemployment."
Right: "The graph shows an increase in unemployment."

Wrong: "Energy consumption in United States rose by 12%."
Right: "Energy consumption in the United States rose by 12%."

Key rules for Task 1:

Use "the" when referring to the specific graph, chart, or map in front of you: "the graph above", "the diagram"
Use "a/an" for first mention of a general thing: "a significant increase", "an upward trend"
Countries with "United" or "Republic" need "the": the United States, the United Kingdom, the Netherlands
Omit the article when using bare nouns generically: "Energy consumption rose." (acceptable) vs. "The energy consumption rose." (awkward)

4. Incorrect Prepositions

Prepositions don't always follow English learner logic. In Task 1, a few pairs cause recurring mistakes.

Wrong: "Sales decreased with 15%."
Right: "Sales decreased by 15%."

Wrong: "The period of 2010 to 2020."
Right: "The period from 2010 to 2020." (or "between 2010 and 2020")

Wrong: "Growth in comparison to the previous year."
Right: "Growth in comparison with the previous year." (or simply "compared to")

Other common Task 1 prepositions:

At a peak/low (not "in" or "on")
In 2020, during the year, throughout the period
Between X and Y (two things); among X, Y, and Z (three or more)
Rise/increase by an amount; rise to a level

5. Passive Voice Errors

Task 1 often requires passive constructions. Mistakes happen when the preposition following "by" is wrong, or when you omit "by" entirely.

Wrong: "The data was collected from questionnaires."
Right: "The data was collected using questionnaires." (or "by questionnaire")

Note: If you're naming the method, use "using" or "by [method]". If you're naming the person, use "by [person]": "The survey was conducted by 500 residents."

Wrong: "The pie chart is shown different spending categories."
Right: "The pie chart shows different spending categories." (Or stay passive: "Different spending categories are shown in the pie chart.")

6. Awkward Comparatives and Superlatives

Comparing two things requires the comparative; comparing three or more requires the superlative. Mixing them loses marks.

Wrong: "France has the highest growth rate compared to Germany."
Right: "France has higher growth than Germany." (two things = comparative)

Right: "Among the three nations, France has the highest growth rate." (three or more = superlative)

Also watch for doubling: "more better" and "most highest" are common mistakes from learners whose first language patterns differently.

7. Missing or Dangling Prepositions in Descriptions

When describing a process or sequence, forgetting a preposition creates fragments.

Wrong: "First, water is added the mixture."
Right: "First, water is added to the mixture."

Wrong: "The product is divided three sections."
Right: "The product is divided into three sections."

8. Comma Splices and Run-Ons

Joining two independent clauses with only a comma creates a comma splice. Task 1 demands clean punctuation.

Wrong: "The graph shows an increase in sales, it peaked in 2015."
Right: "The graph shows an increase in sales, and it peaked in 2015."
Also right: "The graph shows an increase in sales. It peaked in 2015."

Use a conjunction (and, but, or, yet), a semicolon, or split into two sentences.

How to Spot These Errors in Your Own Writing

After you finish Task 1, spend 2–3 minutes on a focused proofread:

Circle every verb and check the subject matches (singular or plural).
Check all tenses: are they consistent, or do you have a valid reason to change?
Find every article (a, an, the) and every preposition. Ask yourself: is this the only correct choice, or could another work?
Read aloud. Run-ons and fragments sound wrong when spoken.

These eight errors are frequent precisely because they're easy to make under pressure. Awareness alone cuts your error rate significantly. If you drill a few examples of each before test day, you'll recognise and fix them in real time.