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Teacher led

GCSE English Language essays AI marking, 40 marks

Accuracy: Put 34 essays in almost the same order as the definitive marks, but marked them an average of 7.4 marks lower. Average gap of 7.6 marks, so the teacher marks and DeepMark gives a second opinion.

Exemplars
34
Questions worth
40 marks
Marked lower
33 of 34
Engine version
2026.11.04
Tested
6 November 2026

By DeepMark Labs Limited. Last updated 8 November 2026.

How to use DeepMark here: Teacher led. The teacher marks. DeepMark acts as a second opinion: it checks consistency against the mark scheme and flags anything the teacher may want to look at again. The teacher’s mark always stands.

Engine version 2026.11.04, a small sample, and run by DeepMark itself. Method and limits

What DeepMark does well

DeepMark put 34 GCSE English Language 40 mark essays in almost the same order as the definitive marks, with a ranking correlation of 0.91. Stronger essays got higher marks and weaker essays got lower ones.

It is also consistent. In our repeatability study, 156 of 156 essays stayed in the same level on all 5 runs. The same essay gets the same mark every time.

The limit

DeepMark marks these essays lower than the definitive mark: lower on 33 of 34, by 7.4 marks on average. The average gap was 7.6 marks, 12 of 34 were within 4 marks, and none matched exactly. Average accuracy was 81.1% and median accuracy 85%.

The gap grows with the mark. On essays the exam board gave 20 or fewer, DeepMark was 2.5 marks lower on average. On the 10 essays given full marks, it was 12.2 marks lower.

12 of 34 essays were within 4 marks of the definitive mark
Exact: 0 essays001 mark: 4 essays412 marks: 2 essays223 marks: 2 essays234 marks: 4 essays445 marks: 2 essays256 marks: 4 essays467 marks: 0 essays078 marks: 1 essays189 marks: 2 essays2910 marks: 3 essays31011 marks: 0 essays01112 marks: 3 essays31213 marks: 1 essays11314 marks: 4 essays41415 marks: 0 essays01516 marks: 2 essays216

Gap from the definitive mark, in marks (0 means exact)

How to use DeepMark on 40 mark essays

First draft

Questions up to 16 marks

DeepMark drafts the mark, and the teacher checks it.

Teacher led

40 mark essays and A level essays

Second opinion mode. The teacher marks, and DeepMark checks consistency and flags gaps.

On long essays, DeepMark’s strength is consistency. It marks the same essay the same way every time: 264 of 264 school answers got the same mark on all 5 runs in our repeatability study. Long English essays are where human markers disagree most. So the teacher marks, and DeepMark keeps the whole department to one standard.

This is consistent with a Cambridge led study (May 2026) of over 750 undergraduate essays, which found artificial intelligence matched human grade bands only 35 to 65% of the time, and suggested it as a second pair of eyes, with a human always setting the final mark. Those were university essays, not GCSE answers.

Marks against the definitive mark

12 of 34 essays worth 40 marks were within 4 marks of the definitive mark
001010202030304040Definitive mark 40, DeepMark 35: 1 essayDefinitive mark 40, DeepMark 30: 2 essaysDefinitive mark 40, DeepMark 28: 2 essaysDefinitive mark 40, DeepMark 27: 1 essayDefinitive mark 40, DeepMark 26: 2 essaysDefinitive mark 40, DeepMark 24: 2 essaysDefinitive mark 39, DeepMark 25: 1 essayDefinitive mark 36, DeepMark 22: 1 essayDefinitive mark 30, DeepMark 24: 1 essayDefinitive mark 30, DeepMark 21: 1 essayDefinitive mark 30, DeepMark 18: 1 essayDefinitive mark 29, DeepMark 24: 1 essayDefinitive mark 29, DeepMark 21: 1 essayDefinitive mark 27, DeepMark 17: 1 essayDefinitive mark 26, DeepMark 20: 1 essayDefinitive mark 24, DeepMark 18: 1 essayDefinitive mark 22, DeepMark 21: 1 essayDefinitive mark 22, DeepMark 13: 1 essayDefinitive mark 21, DeepMark 20: 1 essayDefinitive mark 20, DeepMark 23: 1 essayDefinitive mark 20, DeepMark 16: 2 essaysDefinitive mark 19, DeepMark 16: 1 essayDefinitive mark 15, DeepMark 13: 1 essayDefinitive mark 14, DeepMark 8: 1 essayDefinitive mark 13, DeepMark 12: 1 essayDefinitive mark 12, DeepMark 8: 1 essayDefinitive mark 11, DeepMark 10: 1 essayDefinitive mark 10, DeepMark 8: 1 essayDefinitive mark 9, DeepMark 5: 1 essayDefinitive mark (out of 40)DeepMark mark (out of 40)
  • Same mark as the definitive mark
  • Within 4 marks
  • Essays within 4 marks
  • Essays further away
  • Larger dots hold more essays.

Ranking correlation measures order. The average gap above is the accuracy figure.

Accuracy over time

First measured on engine version 2026.11.04, tested 6 November 2026. Every time we change the marking engine we test these same answers again, and each result adds a point to a trend line here.

How we tested it

  1. 1We collected real GCSE English Language answers to 40 mark writing questions that the exam board publishes with the mark it awarded, from several exam series.
  2. 2We loaded each question paper and its mark scheme into DeepMark from the original documents.
  3. 3The handwritten essays were typed up before marking, keeping the students' spelling and punctuation.
  4. 4Each essay was marked by the same marking engine teachers use. Nothing was tuned on these essays.
  5. 5We compared DeepMark's whole mark with the definitive mark for every essay.

Every mark

Every essay in the study, with the definitive mark and DeepMark’s mark. We publish marks only, never student writing.

Every mark, answer by answer (34 exemplars)Show
ExemplarQuestion worthDefinitive markDeepMark markDifference
14040355 marks lower
240403010 marks lower
340403010 marks lower
440402812 marks lower
540402812 marks lower
640402713 marks lower
740402614 marks lower
840402614 marks lower
940402416 marks lower
1040402416 marks lower
1140392514 marks lower
1240362214 marks lower
134030246 marks lower
144030219 marks lower
1540301812 marks lower
164029245 marks lower
174029218 marks lower
1840271710 marks lower
194026206 marks lower
204024186 marks lower
214022211 mark lower
224022139 marks lower
234021201 mark lower
244020233 marks higher
254020164 marks lower
264020164 marks lower
274019163 marks lower
284015132 marks lower
29401486 marks lower
304013121 mark lower
31401284 marks lower
324011101 mark lower
33401082 marks lower
3440954 marks lower

How to read these numbers

Average gap
How far DeepMark's mark was from the definitive mark, on average, ignoring direction. A gap of 1.3 marks means a typical answer was a little over 1 mark away.
Matched exactly
DeepMark gave the same whole mark as the definitive mark. This is the strictest test, and only possible because every DeepMark mark is a whole mark.
Within 1 mark
DeepMark's mark was the definitive mark or 1 mark either side.
Ranking correlation
How closely DeepMark puts answers in the same order as the definitive mark, from 0 to 1. It measures order, not accuracy, so we always show it beside the average gap, never instead of it.

Questions teachers ask

How accurate is DeepMark on GCSE English Language essays?

On 34 GCSE English Language 40 mark essays, DeepMark's marks were an average of 7.6 marks from the definitive mark and 7.4 marks lower on average. It put the essays in almost the same order as the definitive marks, with a ranking correlation of 0.91.

How should I use DeepMark on 40 mark essays?

Mark the essay yourself and use DeepMark as a second opinion. It checks your mark against the mark scheme and flags anything you may want to look at again. Your mark always stands.

What is DeepMark good at on long essays?

Consistency. In our repeatability study, 156 of 156 essays stayed in the same level on every one of 5 runs. Long essays are where human markers disagree most, so one consistent second opinion helps a department mark to one standard.

Other studies