Editing is proofreading a piece of writing to correct errors in grammar and other mechanical problems, whereas revising involves going over the writing to check for logic, clarity, flow, organization and adherence to purpose. Editing fixes specific mistakes on a sentence level, so an editor who is not the writer can successfully accomplish it, but because revising is an analysis of the overall piece of writing, the original author needs to do it.
In addition to ensuring that a piece of writing adheres to the rules of grammar, editing targets mistakes in spelling, punctuation, word choice and syntax. However, revising emphasizes how closely the author comes to the original purpose of the writing. The writer must focus the piece to clarify the theme or thesis and divide the paper into well-organized paragraphs. Revising often involves changing the order of the paragraphs so they flow better and have smooth transitions from one to the next. Each paragraph needs a clear topic sentence, supporting middle sentences and a transitional statement or conclusion.
To clarify and streamline the piece of writing during revision, the writer may need to delete redundant sentences and paragraphs, rewrite vague passages, and add additional text. Although some sections may be interesting, an author needs to excise them if they do not contribute to the larger theme. Revising puts the author in the reader's perspective when evaluating the paper as a whole for clarity and voice.