> The text of Etymonline is built entirely from print sources, and is done entirely by human beings. Ngrams are not.

I'm confused about this part actually. I assume by "entirely from print sources" it means it does not include digital sources? That doesn't sound very relevant to the issues mentioned in the article though: unless it uses the "complete" set of all print source, it totally could have the same skewed-dataset issues too; and humans can make the same mistake as OCR does.