Hacker News front pageJul 21, 2026, 00:36 UTC+8

Over 30% of new arXiv submissions read as AI-written, CS hits 65%

Over 30% of new ArXiv submissions now read as AI-written

Unslop scanned 12,750 arXiv full-text papers with a detector calibrated to a 0.4% false-positive floor. The flagged share peaked near 39% in early 2026; CS leads at ~65%, math sits at 0.7%. Math's low score may reflect sparse prose and detector blind spots rather than low adoption. The post treats the numbers as a lower bound on machine-like writing prevalence, not authorship proof.

Why it matters: Unslop scanned 12,750 arXiv full texts with a detector calibrated to 0.4% false positives on pre-ChatGPT papers, finding ~32% of 2026 submissions read as machine-written. Transparent method, concrete numbers, field-level breakdown. Not clickbait. Score held below 85 because it...

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The reason this is worth a click: Unslop anchored their detector to a 0.4% false-positive floor using pre-ChatGPT papers as ground-truth human text, so the 32% figure is net of that baseline. CS at 65% isn't surprising, but math at 0.7% is the more telling number. Math papers are mostly notation and theorem-proof structure—strip out equations and references, and the remaining prose is sparse and out-of-distribution for a detector trained on standard scientific English. Unslop openly flags this: a low score in math could mean low AI adoption or a detector blind spot, and their data can't separate the two. I'd treat these numbers as a lower-bound estimate of machine-like writing style, not proof of authorship. The detector only answers 'does this read like a machine wrote it,' not 'did a machine write it.'

Source: Hacker News front page · unslop.run
Published: Jul 21, 2026, 00:36 UTC+8 · Jul 21, 2026