Professional editors are usually meticulous and detail-orientated perfectionists. They do their utmost to detect and correct all the errors in a manuscript. Their reputations and livelihoods depend on this.
But what constitutes an error is subjective. A strict grammarian may consider a comma splice unacceptable, but an author may choose to use them in every paragraph. References like the Chicago Manual of Style provide guidelines, but punctuation, especially in fiction writing, is more often influenced by pacing, nuance and author preference than by what some consider as the rules.
Despite multiple passes through the manuscript, some errors may remain, either because the editor missed them, or because they didn’t recognise them in the first place. Although editors may have excellent training, the latest dictionaries and the best intentions, no one person can know everything about our vast, complicated and ever-evolving English language. The book publishing industry knows this and allows a certain tolerance for a small percentage of remaining errors. It’s expected as part of the process.
Although editors can’t guarantee that the editing will be perfect, they can certainly ensure that the text is vastly improved. For example, if an 80 000-word manuscript contains 500 irrefutable errors and your editor spots and corrects 480 of them, that’s a 96% catch rate, which is a pretty good score by most standards.
If funds allow, some authors employ a second proofreader and a person with fresh eyes and slightly different training and skills will usually catch most of the remaining errors.
However, rather than using percentages to express an acceptable error rate, it’s better to think of editing as enhancing the text and making it clear and consistent.
While we may aim for a perfect edit, it’s not always achievable. An excellent edit is a more realistic outcome.
Thanks to Tracy Buenk for the words! 📝