Measuring Artifact Reliance in Machine-Generated Text Detectors

Anastasia Voznyuk, Andrey Grabovoy


Abstract
Detectors of machine-generated text score almost perfectly on scientific-literature benchmarks, implying we can reliably distinguish with these detectors human and machine-generated documents. We looked at ten scientific-document subsets from six popular resources, and on several of them that apparent ease is a side effect of how the documents were put together. A logistic regression using 27 superficial features reached 0.833-0.997 macro-F1, and on the three arXiv subsets it outperformed every detector we evaluate with F1-scores 0.951–0.997. The strongest cue to the detector is the PDF extraction artifact: human texts retain their original line breaks, whereas generated texts are extracted as a single block of prose. This cue, together with three other formatting features, tell the classes apart at 0.996 AUC. To distinguish benchmarks that contain such a signal from detectors that rely on one, we introduce format counterfactuals: just re-wrapping a machine-written abstract without changing a single word reverses 20-27% of a public detector’s correct decisions. Normalizing formatting before training reduces the generalization gap from 0.32 to 0.22. On format-clean benchmarks, it also raises out-of-domain macro-F1 from 0.33 to 0.65 for detectors trained on artifact-containing subsets. We release our tools and scripts to reconstruct the corrected subsets.
Anthology ID:
2026.docinsights-1.13
Volume:
The Proceedings of Workshop on Document Intelligence and Understanding
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Santosh T.Y.S.S., Amit Agarwal, Vivek Gupta, Yova Kementchedjhieva, Aparna Garimella, Yufang Hou
Venues:
DocInsights | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
174–185
Language:
URL:
https://aclanthology.org/2026.docinsights-1.13/
DOI:
Bibkey:
Cite (ACL):
Anastasia Voznyuk and Andrey Grabovoy. 2026. Measuring Artifact Reliance in Machine-Generated Text Detectors. In The Proceedings of Workshop on Document Intelligence and Understanding, pages 174–185, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Measuring Artifact Reliance in Machine-Generated Text Detectors (Voznyuk & Grabovoy, DocInsights 2026)
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PDF:
https://aclanthology.org/2026.docinsights-1.13.pdf