A copy editor has many tasks, all in the name of effective communication. Ultimately, copy editors ensure that a manuscript conforms to the publisher’s editorial style. Style guides, and therefore copy editors, typically focus on the following principles: Correctness, Clarity, and Consistency.
Correctness: The manuscript must be correct. Copy editors fix grammatical errors, spelling mistakes, punctuation problems, and tense inconsistencies. They also fact check for accuracy in place/people names and dates.
Clarity: Consider a copy editor an advocate for your reader. Everything must make sense so there is no unintentional ambiguity. Additionally, a copy editor will ensure that each sentence is logical on its own as well as in its place in the surrounding text.
Consistency: A copy editor must make sure that usage is consistent throughout the text. For instance, “e-mail” and “email” are both considered correct, but a manuscript that alternates the spelling is sloppy and jarring to the reader.
The Style Sheet: A copy editor records editorial choices on a style sheet to be returned to the author for reference. The style sheet will travel with the manuscript to any future editor/publisher working on the document.