You're staring at two bar charts. One shows coffee consumption in 2010. The other shows 2020. You need to compare them. Sounds straightforward, right? It's not.
Most students crash on grammar in Task 1 precisely when they're trying to compare. They'll write "Coffee consumption increased more than tea consumption" without realizing the structure's broken, or they'll mix up comparative adjectives so badly that examiners dock them points for Grammatical Range and Accuracy.
Examiners aren't hunting for perfect prose. They're hunting for control. And control means spotting your own errors before the grader does. This guide shows you exactly where comparison structures fall apart in IELTS writing task 1, and how to fix them before they cost you band points.
Task 1 is about describing trends and changes. You've got 150 words. You're under time pressure. And you're comparing two or more data sets while sounding coherent. Your brain short-circuits.
The Band Descriptor for Grammatical Range and Accuracy says examiners look for whether you use a variety of complex structures accurately. Comparisons are complex. They're also where students default to simple, repetitive patterns or slip into careless mistakes that examiners catch immediately.
Look at this one: "The sales of Product A is higher than Product B." The subject is plural (sales), so the verb should be "are," not "is." That's not a typo. That's a control issue. And examiners clock it right away.
Structure 1: Comparative Adjective + Than
This is the backbone of Task 1. You compare one thing to another using an adjective in comparative form.
Wrong: "The consumption of tea was more lower than coffee in 2015."
"More lower" is a double comparative. You pick one format: either "lower" or "more low" (though "more low" sounds awkward). The right form is just "lower."
Right: "Tea consumption was lower than coffee consumption in 2015."
See how clean that is? One comparative adjective. Clear comparison. Done.
Structure 2: As...As (Comparing Similar Things)
When two things are roughly the same, use "as [adjective] as."
Wrong: "In 2010, coffee sales were as high like tea sales."
Wrong word. The structure is "as...as," not "as...like."
Right: "In 2010, coffee sales were as high as tea sales."
Structure 3: Comparative + And Comparative (Showing Trends)
This describes something getting progressively higher or lower. The pattern is: [comparative adjective] and [comparative adjective].
Wrong: "Oil prices rose higher and higher, reaching more expensive levels by 2019."
This mixes comparative and superlative awkwardly. "Higher" is fine, but "more expensive" breaks the repetitive pattern. Keep it consistent.
Right: "Oil prices rose higher and higher, reaching peak levels by 2019."
Or: "Oil prices became progressively more expensive, peaking in 2019."
You've heard about subject-verb agreement since Year 7. So why does it collapse in Task 1 comparisons?
Your brain is juggling the comparison, the data, the time frame, and the word count. The verb becomes invisible.
Wrong: "The number of visitors to both museums were increasing across the decade."
The subject is "number" (singular), so use "was," not "were."
Right: "The number of visitors to both museums was increasing across the decade."
Or rewrite to avoid the awkward singular: "Visitor numbers at both museums increased across the decade."
Quick fix: Circle your subject and your verb before you finish. Read them together out loud. Does the verb sound right with the subject? If you hesitate, rewrite. Task 1 doesn't reward sounding natural. It rewards being correct.
Parallelism means matching grammatical patterns when you list or compare multiple things. It should be obvious. It isn't.
Wrong: "Between 2000 and 2020, car sales grew significantly while bicycle sales declined and motorcycles were less popular."
Look at what's being compared: "car sales grew," "bicycle sales declined," and "motorcycles were less popular." The structures don't match. Car and bicycle sales get active verbs. Motorcycles gets a different construction entirely.
Right: "Between 2000 and 2020, car sales grew significantly, bicycle sales declined, and motorcycle sales fell sharply."
Now all three follow the same pattern: [sales noun] + [verb] + [descriptor]. The Band Descriptor mentions "accurate use of less common structures." Parallelism in comparisons is less common. Get it right, and examiners notice it. Get it wrong, and they notice faster.
Want a higher band? You'll need complex structures. The trap is building comparisons into dependent clauses. That's smart. But it's also where errors hide.
Wrong: "While electricity consumption, which had been increasing steadily, was higher than gas consumption, the latter category showed surprising growth in 2018."
This is muddled. There's a relative clause ("which had been increasing steadily") nested inside the main comparison. The reader loses track of what's being compared to what. Plus "the latter" is ambiguous. Does it mean gas consumption or the whole previous clause?
Right: "Electricity consumption, which had been steadily increasing, remained higher than gas consumption. However, gas consumption showed surprising growth in 2018."
Two sentences. Each comparison stays clear. The relative clause sits in its own space. Examiners reward this kind of control. If you need help with other structural issues in Task 1, check our guide on common sentence structure mistakes.
Real talk: In Task 1, clarity beats complexity every time. A simple, correct sentence scores higher than a complex, tangled one. If a complex structure makes your comparison harder to follow, simplify it.
You've learned that passive voice sounds formal. In Task 1, formality helps, right? Not always. Passive voice in comparisons can hide who or what you're comparing.
Wrong: "A higher percentage of revenue was generated by digital sales compared with what was produced by traditional retail."
Grammatically correct, but bloated and weird. "What was produced" is especially painful because revenue isn't "produced"; it's "generated."
Right: "Digital sales generated a higher percentage of revenue than traditional retail."
Active voice. Clear. Punchy. The comparison jumps out. You also save 7 words on your 150-word limit, giving you space for more detail or variety.
You've got 20 minutes for Task 1. You can't spend 5 minutes hand-parsing every sentence. But you can spend 90 seconds on this final scan.
Spend 90 seconds here, and you'll catch 70% of the comparison errors that cost students band points. That's not perfect, but perfect isn't the goal in Task 1. Control is.
Prompt: The charts below show the average house prices in four capital cities over a 20-year period. Compare and describe the main features.
Here's a weak response:
Weak: "London house prices was significantly more higher than the other three cities throughout the period. Paris and Berlin saw rapid increases, while Madrid remained steady. London was more expensive, Paris was more expensive, and Berlin was also more expensive compared with Madrid. The growth in London and Paris were remarkable, whereas Madrid had less increase."
Errors: "was significantly more higher" (double comparative + subject-verb disagreement), "saw rapid increases, while Madrid remained steady" (verb tense shift in the comparison), "was more expensive" repeated three times (robotic repetition), "The growth...were" (subject-verb disagreement), "had less increase" (awkward, should be "grew less" or "saw less growth").
Strong: "London experienced significantly higher house prices than the other three cities throughout the entire period. Paris and Berlin both saw rapid increases, whereas Madrid remained relatively stable. London consistently outperformed Paris and Berlin in terms of price growth, with all three capitals becoming more expensive than Madrid. By the end of the period, London's growth trajectory had been steeper than both Paris and Berlin, which in turn exceeded Madrid's steady but modest increases."
What changed: Clear comparative structures ("significantly higher than"), consistent verb tenses, varied sentence patterns, accurate subject-verb agreement, and natural flow that shows relationships without repetition. For more on describing data accurately in Task 1, see our post on common data description errors.
Spotting these errors manually takes time. An IELTS writing checker uses grammar rules and pattern recognition to flag double comparatives, subject-verb disagreement, passive voice issues, and parallelism mistakes before they reach an examiner. Using a free IELTS writing checker on your Task 1 draft catches errors while you still have time to rewrite. The best tool for this is one specifically designed for IELTS writing correction, not generic grammar checkers that don't understand band descriptors or Task 1 requirements.
Use an IELTS writing task 1 comparison checker to spot grammar mistakes in your chart comparisons instantly. Get real feedback on comparative structures, subject-verb agreement, and parallelism before you submit.
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