Perkins et al. 2024: AI detectors against adversarial techniques

Authors
Perkins, Roe, Vu, Postma, Hickerson, McGaughran, Khuat
Venue
International Journal of Educational Technology in Higher Education 21, article 53
Published
AIDI-S-0005

Updated ·

The 2024 Perkins study ran 114 text samples through seven AI detectors and found a mean accuracy of 39.5% on unmanipulated AI text, falling by a further 17.4% once six adversarial techniques were applied. The journal version, "Simple techniques to bypass GenAI text detectors: implications for inclusive education" by M. Perkins and six co-authors, was published in the International Journal of Educational Technology in Higher Education on September 9, 2024 (DOI 10.1186/s41239-024-00487-w).

Perkins et al. 2024: AI detectors against adversarial techniques: register plate with the page title and its register ID
The record plate: register ID and title, drawn from the index data.

This record is one of eight in the studies index. The March 2024 preprint carried a different title (arXiv 2403.19148); the headline figures are identical in both versions. Perkins 2024 measures evasion directly: every manipulation was made by the generative tool that wrote the text, none by hand.

Perkins 2024 lists seven detectors and reports results for all seven, although the abstract and methods say "six"; the inconsistency is the paper's own.

What was tested

Detectors tested

The 7 detectors tested and their index cards
DetectorVersion or access statedIndex card
Turnitin AI detectLicence held by the lead author's institutionTurnitin
GPTZeroFree versionGPTZero
ZeroGPTFree version, retrieved March 3, 2024ZeroGPT
CopyleaksPurchased creditsCopyleaks
CrossplagFree versionno card
GPT-2 Output Detector (OpenAI)Free versionGPT-2 Output Detector
GPTKitPurchased creditsGPTKit

Sample

The sample as the paper describes it
Text typeCountSource
Original AI samples15GPT-4, Claude 2 and Bard, 5 each, about 500 words
Adversarially altered AI samples89Six techniques (spelling errors, burstiness, paraphrase, lower complexity, non-native English voice, higher complexity), all applied by the generating tool
Human-written controls10Written by the researchers

Detectors as listed in Perkins et al. 2024, DOI 10.1186/s41239-024-00487-w.

The sample started from 15 AI texts of about 500 words each. Perkins 2024 then produced 89 altered versions with six adversarial techniques (one case failed, so 89 rather than 90) and added 10 human-written controls, for 114 samples and 805 tests, of which 797 were valid (arXiv PDF).

Sample as described in Perkins et al. 2024, journal version.

Perkins 2024 reused the five-step classification from Weber-Wulff 2023 and computed accuracy by the binary, semi-binary and logarithmic methods plus their mean. False accusations (FAS) and undetected cases (UDC) count false and partially false verdicts at a 60% threshold (DOI 10.1186/s41239-024-00487-w).

What the study reports

Results as the study reports them, with their base
MetricValueBase
Baseline mean accuracy, Copyleaks (rank 1)64.8%15 AI samples and 10 human samples
Baseline mean accuracy, Turnitin61%15 AI and 10 human samples
Baseline mean accuracy, ZeroGPT46.1%15 AI and 10 human samples
Baseline mean accuracy, GPTZero (rank 7)26.3%15 AI and 10 human samples
Mean accuracy, original AI samples, all tools39.5%15 AI samples, 7 tools
Accuracy before and after manipulation, Copyleaks73.9% to 58.7% (drop 15.2%)mean of three methods, Table 8
Before and after, ZeroGPT31.3% to 17.3% (drop 14%)mean of three methods, Table 8
Before and after, GPTZero26.4% to 16.7% (drop 9.7%)mean of three methods, Table 8
Before and after, Turnitin50% to 7.9% (drop 42.1%)mean of three methods, Table 8
Before and after, GPTKit6% to 4.5% (drop 1.5%)mean of three methods, Table 8
False accusations, Copyleaks5 (FAS 50%)10 human samples
False accusations, GPTZero1 (FAS 10%)10 human samples
False accusations, Turnitin, ZeroGPT, GPT-2 Output, GPTKit0 (FAS 0%)10 human samples
Undetected cases, GPTZero (fewest)58 (UDC 55%)104 AI samples
Undetected cases, Copyleaks41 (UDC 39%)104 AI samples

The table gives baseline mean accuracy (Table 7 of the paper), before-and-after figures under manipulation (Table 8) and error counts (Table 10) as printed in Perkins 2024, for the detectors with a card plus the top and bottom of each table (arXiv PDF).

Values as printed in Perkins et al. 2024, Tables 7, 8 and 10, DOI 10.1186/s41239-024-00487-w. Table 8 baseline figures differ from Table 7 for the same tools; both are as the paper prints them.

Perkins 2024 reports low numbers before any manipulation: mean accuracy of 39.5% on the original AI samples and 67% on the human controls across seven tools (DOI 10.1186/s41239-024-00487-w). Copyleaks detected 64.8% of AI texts in Perkins 2024, followed by Turnitin at 61%, with GPTZero at approximately 26%.

The generator mattered in Perkins 2024: Bard output was identified 76.9% of the time, GPT-4 23.9% and Claude 2 17.7% (journal version).

Manipulation cut accuracy to a mean of 22.1% across the six techniques in Perkins 2024, a drop of 17.5% (arXiv PDF). Spelling errors were the strongest technique in Perkins 2024 at 12.9% accuracy (a 27% drop), then burstiness at 15.9% (24% drop), paraphrase at 18.4% (21% drop), lower complexity at 21% (19% drop) and non-native voice at 27.7% (12% drop); higher complexity barely moved at 37% (2% drop). After manipulation, Copyleaks held the highest accuracy in Perkins 2024 at 58.7% and GPTKit the lowest at 4.5%, while Turnitin showed the largest drop, 42.1%.

Limits the authors state

The authors restrict the findings to a relatively small number of samples, three generative tools and seven detectors, which they say do not cover the range of writing styles, manipulations or tools, and to a specific snapshot in time.

The spelling-error samples, the strongest evasion, are ones the authors say a student would be very unlikely to submit. Eight samples failed to process on some tools in Perkins 2024, which is why 797 of 805 tests were valid. No corrigendum is recorded (DOI 10.1186/s41239-024-00487-w).

Which cards this study feeds

Six of the seven detectors in Perkins 2024 have a card in this index; the GPTKit card, added on 10 November 2026 with the ninth wave, carries its 6% mean accuracy on unmanipulated AI text falling to 4.5% after adversarial techniques, the lowest post-manipulation figure of the seven, and 0 false accusations in 10 human samples. Each card quotes each quoting the baseline, the post-manipulation figure and the error counts with their bases; the GPT-2 Output Detector card, added on 9 November 2026, carries its 57.2% baseline, the fall from 34.7% to 17.5%, 0 false accusations in 10 and 81 of 104 undetected.

All six appear in the ranking of detectors by independent test record. Since 9 November 2026 the post-manipulation figures feed the robustness ranking, where Copyleaks' 58.7% is the highest Perkins figure and GPTKit's 4.5% the lowest of the seven (GPTKit's ranked value is the higher 30% from Orenstrakh 2023 under the highest-printed rule, and the 4.5% stays in its base), and the undetected counts feed the false negative rate ranking. How this record is sourced explains how a before-and-after result is stored on a card, and the home page lists which AI detectors exist and who has tested them.

Related records: Weber-Wulff 2023 supplied the classification scale; the RAID benchmark tests eleven attacks at scale.

Questions about this study

How much did adversarial edits reduce detector accuracy in Perkins 2024?

By 17.4% on average: Perkins 2024 reports mean accuracy falling from 39.5% on unmanipulated AI text to 22.2% after manipulation across seven detectors (DOI 10.1186/s41239-024-00487-w). Turnitin fell furthest in Perkins 2024, from 50% to 7.9%, while GPTKit, already at 6%, fell 1.5%.

Which evasion technique worked against detectors in Perkins 2024?

Adding spelling errors: accuracy on those samples was 12.9% in Perkins 2024, a 27% drop, followed by increased burstiness at 15.9% and paraphrase at 18.4% (arXiv PDF). Increasing complexity was the weakest technique in Perkins 2024 at 37% accuracy, a 2% drop, and the authors note students would be unlikely to submit the misspelled versions.

Did detectors falsely accuse human writers in Perkins 2024?

Three of seven did: Perkins 2024 counts 5 false accusations in 10 human samples for Copyleaks (FAS 50%), 3 for Crossplag (30%) and 1 for GPTZero (10%) (journal version). Turnitin, ZeroGPT, the GPT-2 Output Detector and GPTKit recorded 0 false accusations in Perkins 2024.

Which generator was hardest to detect in Perkins 2024?

Claude 2: Perkins 2024 reports that 17.7% of Claude 2 outputs were correctly identified, against 23.9% for GPT-4 and 76.9% for Bard (DOI 10.1186/s41239-024-00487-w). Each generator wrote 5 of the 15 original samples in Perkins 2024.

Source and revisions

Source

Perkins, M., Roe, J., Vu, B. H., Postma, D., Hickerson, D., McGaughran, J., Khuat, H. Q. (2024). Simple techniques to bypass GenAI text detectors: implications for inclusive education. International Journal of Educational Technology in Higher Education 21, article 53. https://doi.org/10.1186/s41239-024-00487-w. Preprint arXiv:2403.19148 (March 2024, as "GenAI detection tools, adversarial techniques and implications for inclusivity in higher education").

Revision log

  1. Record created
  2. Gptkit row linked to the new card (ninth wave), six of seven tools carded

Corrections log

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