Here's something that should be of interest to writing, reading, and data-analytics folks: Forensic Linguistics.
"According to forensic linguists, the experts who investigate a text’s
originator, if they have an individual’s known writings, they can detect
with up to 95% accuracy that person’s authorship of any other document."
I had professors in college years ago who swore they could tell when someone had her boyfriend write her paper for her, etc., because the writing style was just so different from how the person usually wrote. This age-old gut instinct analysis is now getting some help from the IT world.