Stylometry
Updated June 10, 2026
The statistical analysis of writing style — the centuries-old discipline that AI detection quietly inherited.
Definition
Stylometry quantifies writing style: sentence-length distributions, function-word frequencies (the, of, but), punctuation habits, vocabulary richness. Because these habits are largely unconscious, they fingerprint authors — famously used to attribute the disputed Federalist Papers, unmask Robert Galbraith as J.K. Rowling, and support forensic authorship cases.
Stylometry and AI detection
An AI detector is stylometry pointed at a new author: the model. LLMs have unusually stable unconscious habits — even rhythm (low burstiness), safe word choices (low perplexity), signature phrasing — making "machine" one of the most identifiable styles ever measured.
The flip side: your own fingerprint
Stylometry also explains the detection methods no score shows: an instructor comparing your essay to your in-class writing is doing informal stylometry, and voice discontinuity is evidence detectors can't provide. It cuts the other way too — your genuine quirks, preserved, are the strongest "human" signal there is. That's an argument for humanizing toward your own voice, not toward generic smoothness.