Closest to the official score in this three-product test
For practice, the useful question is not whether a scorer occasionally lands on the right number, but how close it stays to official scoring overall. On the same 73 officially scored responses, IELTS Writing Checker had the lowest average error: 0.49 bands, versus 0.90 for Engnovate and 1.62 for Writing9.
Put more simply, 78.1% of our scores were within 0.5 bands of the official result and 89.0% were within one band. IELTS Writing Checker also had the lowest error in every task and source group shown below.
Overall accuracy comparison
These three measures show both the average distance from the official score and how often a score stayed inside a practical 0.5- or 1-band range.
The average distance between a product score and the official score. Lower is better.
The share of scores no more than 0.5 bands away from the official score. Higher is better.
The share of scores no more than one band away from the official score. Higher is better.
Closer on Task 1 and Task 2
Task 2 was the hardest group for all three products. Even so, IELTS Writing Checker had the lowest average error in Academic Task 1, General Training Task 1, and Task 2.
The same result across three official sources
We repeated the comparison separately for IELTS website samples, Official IELTS Practice Materials, and Cambridge IELTS 18–20. IELTS Writing Checker was closest in all three groups.
Where did the 73 official responses come from?
As of July 2026, we found 73 official responses that could be fully checked against the current IELTS Writing criteria. Each needed a complete task, a complete response, and a verifiable numeric overall score. Duplicate publications and model answers without a score were not counted. Under that rule, 73 is the complete set we could locate—not a sample selected from a larger eligible pool.
The Cambridge series has many older books, but IELTS introduced its revised Writing scales in May 2023. Cambridge IELTS 18 was published in July 2023, making it the first volume released after that change. We therefore used books 18, 19, and 20 so this comparison reflects the scoring framework candidates use today. Earlier books remain useful practice material.
The 73 responses comprise 27 IELTS website samples, 20 from Official IELTS Practice Materials 1 and 2, and 26 from Cambridge IELTS 18–20.
How we compared the three products
Test method
- The same 73 tasks and responses were submitted to all three products. The official score was hidden until each product had returned its result.
- Academic Task 1 charts were attached wherever a product supported image upload. Writing9 does not accept images, so every chart-based Academic Task 1 response was scored there without the original chart image.
- Every response was counted in the same way. We then compared each displayed overall score with the official score and calculated the three measures above.
- The lowest score Writing9 displays is “<4”. For calculation, those results were treated as 3.5.
Official references
Start with our readable guides to the scoring criteria and the official sample collection used in this study. The original publications remain linked below.