Research report
Does Turnitin Detect Gemini 3.5 Flash-Generated Essays?
A Benchmark Experiment on Turnitin's Detection of Gemini 3.5 Flash Essays
Cite this research
In a benchmark of 180 Gemini 3.5 Flash-generated essays (147,117 total words), Turnitin achieved 98.35% word-level accuracy, correctly flagging 144,688 words as AI-generated.
According to Turnitin0 Research, Turnitin correctly identified 98.35% of words in Gemini 3.5 Flash-generated essays, with accuracy ranging from 94.36% for Information Technology majors to 99.82% for Business Administration and International Relations.
- 180 articles tested
- Checker: Turnitin
- LLM: gemini-3.5-flash
- 2 linked datasets
- Detection screenshots available
- Published June 30, 2026
Peng, J. (2026). Does Turnitin Detect Gemini 3.5 Flash-Generated Essays?. Turnitin0 Research. https://www.turnitin0.com/research/reports/does-turnitin-detect-gemini-3-5-flash-generated-essays
Licensed under CC0 1.0 Universal. You may copy, modify, distribute, and cite this research—including text, figures, tables, and datasets—without asking permission.
Overview
This report presents a benchmark experiment evaluating Turnitin's ability to detect essays generated by the Gemini 3.5 Flash language model. A total of 180 essays (73,611 words undergraduate, 72,612 words graduate) were submitted to Turnitin, and word-level accuracy was measured across multiple dimensions including domain, major, academic level, and essay length.
- Overall word accuracy: 98.35% (144,688 correct words out of 147,117 total words).
- By domain:
- Humanities: 99.04% accuracy (38,565/38,939 words)
- Business: 99.02% (24,608/24,852)
- Psychology: 98.94% (4,866/4,918)
- Education: 98.63% (4,753/4,819)
- STEM: 97.70% (71,896/73,589)
- By academic level:
- Undergraduate: 98.55% (73,426/74,505)
- Graduate: 98.14% (71,262/72,612)
- By essay length:
- 400-word essays: 98.38% (22,829/23,205)
- 800-word essays: 99.16% (44,623/45,002)
- 1,200-word essays: 97.88% (77,236/78,910)
- By major: Accuracy ranged from 94.36% (Information Technology) to 99.82% (Business Administration and International Relations).
- Dataset: 180 essays generated by Gemini 3.5 Flash, split evenly between undergraduate (90 essays) and graduate (90 essays) levels.
- Domains covered: Business, Education, Humanities, Psychology, and STEM, spanning 30 distinct majors.
- Essay lengths: 400, 800, and 1,200 words (60–61 essays per bucket).
- Evaluation metric: Word-level accuracy — the proportion of words correctly flagged as AI-generated by Turnitin.
- No humanization or post-editing was applied to any essay.
- Scoring unit: accuracy is measured in words. First identify correct paragraphs under the expectation below, then sum the words in those paragraphs for the correct-word count; total words are summed over all counted paragraphs.
- Correct paragraph: a counted paragraph that was flagged as AI. Correct words are the words in those paragraphs.
- References excluded: from a References/Bibliography-style heading onward, those paragraphs are left out of word counts.
- Limited domain coverage: While 30 majors were included, some domains (e.g., Education, Psychology) had only 6 essays each, reducing statistical power for those subgroups.
- Total essays: 180
- Total words: 147,117
- Correctly flagged words: 144,688
- Word accuracy: 98.35%
- Humanities: 99.04% (38,565/38,939 words)
- Business: 99.02% (24,608/24,852)
- Psychology: 98.94% (4,866/4,918)
- Education: 98.63% (4,753/4,819)
- STEM: 97.70% (71,896/73,589)
- Highest accuracy: Business Administration and International Relations (99.82% each)
- Lowest accuracy: Information Technology (94.36%), Mathematics (95.10%), Physics (96.17%)
- Other notable majors:
- Electrical Engineering: 99.55%
- Criminal Justice: 99.53%
- Economics: 99.41%
- Communications: 99.36%
- Pre-Med: 99.30%
- English: 99.24%
- Environmental Science: 99.22%
- Graphic Design: 99.20%
- Political Science: 99.72%
- Accounting: 98.74%
- Marketing: 98.64%
- Education: 98.63%
- Finance: 98.47%
- Chemistry: 98.41%
- Nursing: 98.23%
- Computer Science: 98.20%
- Biomedical Engineering: 98.18%
- Civil Engineering: 98.84%
- Data Science: 98.87%
- History: 98.99%
- Sociology: 96.48%
- Biology: 96.40%
- Mechanical Engineering: 97.24%
- Health Sciences: 97.56%
- Undergraduate: 98.55% (73,426/74,505 words)
- Graduate: 98.14% (71,262/72,612 words)
- 400-word essays: 98.38% (22,829/23,205 words)
- 800-word essays: 99.16% (44,623/45,002)
- 1,200-word essays: 97.88% (77,236/78,910)
Detection report screenshots
Turnitin marks suspected AIGC text in cyan.