Most students lose 2 to 4 band points in Task 1 not because they can't describe data, but because they mess up basic grammar when talking about trends. You'll use past simple, comparative structures, and time expressions constantly. Get those wrong repeatedly, and examiners mark you down for Grammatical Range & Accuracy, even if your ideas are solid.
In this post, I'm showing you the exact grammar mistakes that trap IELTS students when describing trends, plus how to spot and fix them before submission. These aren't rare edge cases. They appear in nearly every Task 1 response. A quick awareness of them will push you from Band 5 clarity into Band 7 precision. Many students also benefit from using an IELTS writing checker to catch these patterns automatically.
You're looking at a line graph showing visitor numbers to a museum from 2010 to 2020. You need to describe what happened. This is where tense choice becomes everything.
The most common mistake? Switching between past simple and present perfect without reason. You've already looked at historical data. The data has already been collected. So you need past tenses, not present perfect.
Weak: "The graph has shown an increase in visitors from 2010 to 2015. Then the numbers have decreased significantly in 2016."
Why is this weak? You're using present perfect ("has shown", "have decreased") for a completed time period. That signals the action might still be happening. But your data ends in 2020. The trend finished. Past simple is cleaner.
Good: "The graph showed an increase in visitors from 2010 to 2015. Then the numbers decreased significantly in 2016."
Notice the shift? Clearer. Tighter. Band 7 examiners like that. Now here's the second tense trap:
Weak: "Visitors rose to 8,000 in 2012 and then fall to 6,500 in 2014."
You switched tenses mid-sentence for no reason. Both actions happened in the past. Use the same tense.
Good: "Visitors rose to 8,000 in 2012 and then fell to 6,500 in 2014."
The third tense mistake happens when you compare. You'll write something like: "In 2010, sales are lower than they were in 2015." Mixing "are" (present) with "were" (past) for the same dataset looks sloppy. Stick with past tense throughout.
Weak: "In 2010, sales are lower than they were in 2015."
Good: "In 2010, sales were lower than they were in 2015." (Or: "Sales in 2010 were lower than in 2015.")
Tip: Before you write your first sentence in Task 1, decide: past tense only, or past plus present perfect? Most Band 6-7 essays use past simple consistently. It's simpler and safer.
This error makes examiners wonder if you understand basic grammar at all. And it happens constantly when students describe data.
The problem usually shows up when you're talking about multiple things rising or falling together.
Weak: "Both the UK and Germany has experienced a significant increase in employment."
"Both the UK and Germany" is plural. It needs "have", not "has". This is a Band 5 mistake. At Band 6+, you can't make it.
Good: "Both the UK and Germany have experienced a significant increase in employment."
Here's another angle on the same problem. You use collective nouns sometimes in Task 1: "data", "information", "a series of figures", "a range of products".
Weak: "The data shows that three different trends have emerged." (In American English, this works. In British English, which IELTS uses, it doesn't.)
Good: "The data show that three different trends have emerged." (British preference: data = plural)
Examiners know you're not a native speaker. They forgive occasional errors. But repeated subject-verb disagreement signals carelessness. The IELTS band descriptors for Grammatical Range & Accuracy at Band 7 include "uses a variety of complex structures with generally accurate control and only occasional errors." Repeated agreement mistakes knock you down to Band 5-6.
Tip: Circle every verb in your Task 1 response. For each verb, ask: "What's the subject? Is it singular or plural?" Write it down if you're unsure. This 30-second check catches most agreement mistakes before submission.
Prepositions are tiny. That's exactly why they trip you up. You're describing a trend: something goes up, down, or sideways. Getting the preposition right matters more than you think.
The weak version sounds natural to some students because they're translating from their first language. But it's not how English works.
Weak: "The number of cars increased to 500,000 in 2015." (This suggests the total reached exactly 500,000 and stopped there.)
What you probably meant: the number had risen at that point, but might have kept climbing. To show a continuous trend or a figure at a point in time, use "by" for the amount of change, or "at" for the specific number.
Good: "The number of cars increased by 50,000 in 2015." (The amount went up by 50K.)
Or: "The number of cars reached 500,000 in 2015." (Or "stood at 500,000".)
Here's another that catches nearly every student:
Weak: "Sales fluctuated between 2010 until 2015."
You can't mix "between" and "until". Pick one structure.
Good: "Sales fluctuated between 2010 and 2015." (Or: "Sales fluctuated from 2010 until 2015.")
And this one shows up often in Task 1 descriptions of comparisons:
Weak: "France was higher in production than Germany."
Grammatically okay, but awkward. Better options: "France produced more than Germany" or "France's production was higher than Germany's".
Good: "France produced more than Germany." (Cleaner, more direct.)
Articles might sound trivial. They're not. Articles show up in the Lexical Resource band descriptor at Band 6-7 level. Misuse them repeatedly and examiners notice.
In Task 1, you're often introducing a trend for the first time, then referring to it again. That's where articles matter.
Weak: "Overall, the most significant change was a 40% rise in internet usage. A rise occurred gradually between 2005 and 2010."
You introduced the rise. Now refer to it with "the", not "a".
Good: "Overall, the most significant change was a 40% rise in internet usage. This rise occurred gradually between 2005 and 2010." (Or: "The rise occurred...")
Here's the pattern: use "a" or "an" the first time you mention something. Use "the" or a pronoun ("it", "this", "that") every time after.
Weak: "A sharp decline happened in sales. A decline lasted for three years."
Good: "A sharp decline happened in sales. This decline lasted for three years." (Or: "The decline lasted...")
Another article slip: describing general facts versus specific data.
Weak: "The tourism is an important sector for the economy."
"Tourism" is uncountable and general. Don't use "the" with uncountable nouns when you're speaking generally.
Good: "Tourism is an important sector for the economy." (General statement, no article.)
Or: "The tourism industry grew by 20%." (Now "tourism" is an adjective modifying "industry".)
You'll compare data constantly in Task 1. "A was higher than B." "C was the highest point." Get these structures wrong and Band 6-7 scores disappear fast.
The biggest mistake? Doubling up comparatives.
Weak: "The growth in Asia was more faster than in Europe."
"More faster" is redundant and incorrect. Choose one form: either "more fast" (awkward but grammatical) or just "faster" (correct and natural).
Good: "The growth in Asia was faster than in Europe."
Similarly with superlatives:
Weak: "The most highest figure was recorded in Q4."
"Most highest" is doubly wrong. Use either "highest" or "most high" (very awkward, never use).
Good: "The highest figure was recorded in Q4."
Here's a structure mistake that's more subtle. When you compare, you sometimes need to repeat the noun or use a pronoun to avoid confusion.
Weak: "Sales in the UK increased more than France." (Did sales in the UK increase more than sales in France, or more than France itself? Confusing.)
Good: "Sales in the UK increased more than those in France." (Using "those" as a pronoun for "sales".)
Or: "Sales in the UK increased more than in France."
The IELTS band descriptors mention that Band 7 writers "use a variety of complex structures." Correct comparative forms aren't complex. They're foundational. But getting them right signals control and polish.
You know the difference between "go" and "goes". That's not the issue. The issue is choosing between related verbs that describe trends, and getting their grammar right.
Think about these near-synonyms: "rise", "increase", "grow", "expand". All describe upward movement. But they have different forms and partners.
Weak: "Profits increased to 50%. Revenue increased by 30%."
Both are technically okay, but they're imprecise. "To" with a percentage suggests an absolute value (profits = 50%). "By" suggests the amount of change (profits went up by 30 percentage points). For consistency and clarity:
Good: "Profits increased by 50%. Revenue increased by 30%." (Parallel structure, clearer meaning.)
Here's another: passive voice misuse in trend descriptions.
Weak: "An increase was experienced by sales from 2010 to 2015."
Passive voice is fine in English, but it sounds clunky here. You don't know WHO experienced the increase, so passive is weaker. Active is stronger.
Good: "Sales increased from 2010 to 2015." (Active, direct, clear.)
One more: infinitive and gerund mistakes. These trip up a surprising number of students.
Weak: "The graph indicates that the trend is to continue rising. Continuing to rise is expected in the next quarter."
Both structures are grammatically okay but awkward together. The second sentence uses a gerund unnecessarily. Simpler is better: "The trend is expected to continue rising." This is clearer and more natural for Task 1.
Good: "The trend is expected to continue rising in the next quarter."
Tip: In Task 1, keep sentences active and direct. Passive voice and complex gerund structures aren't impressive. They just slow readers down. Examiners want clarity first, complexity second.
You've written your Task 1 response. You have maybe 2 minutes left. What do you check?
Don't read it for "flow" or "ideas". You're past that. Read it specifically for grammar. Here's a three-step system:
This takes 90 seconds and catches roughly 80% of grammar mistakes before an examiner sees them. You won't catch everything, but you'll remove the repeated errors that drop your band score. If you want faster feedback, try an IELTS essay checker that gives you instant corrections.
Examiners grade according to band descriptors. Knowing what errors are typical at each level helps you aim higher.
If you're aiming for Band 6, you need to eliminate the Band 5 errors completely. If you're aiming for Band 7, you should almost never make an error, and when you do, it should be a slip, not a pattern.
Most students sit somewhere between Band 5 and 6 in grammar. The jump to Band 6-7 grammar isn't about learning new structures. It's about applying what you know consistently and accurately under time pressure. If you want to see exactly where your grammar stands, use a free IELTS writing correction tool to get instant feedback on these specific errors.
Use our free IELTS writing checker to catch grammar errors in Task 1, get instant band scores, and receive line-by-line feedback on trend description mistakes. Find errors before your examiner does.
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