Exactly. Just think about how bad OCR is when it gets 90% of the words right! With a 90% word accuracy rate, you have roughly between 0.5 and 1 error per sent

Exactly. Just think about how bad OCR is when it gets 90% of the words right! With a 90% word accuracy rate, you have roughly between 0.5 and 1 error per sentence in a typical text. That's not great. The only reason we can interpret a text that's been OCR'ed at 90% accuracy is that humans are good at filling in what the right word should be in the face of a spelling mistake. If it put in random, nonsense words, we'd just struggle and say the OCR software was garbage. The previous paragraph is 91 words. Imagine reading it with 9 random nonsense words in place of real English words.