Different levels of edit, from substantive editing to copy checking to proofreading, ensure that the document is the best it can be in the time available and with the budget provided. I can suggest what I think a document needs, or give you an initial estimate of effort and cost. As the author, you have the final decision about how much you want accomplished, in what timeframe, and at what expense.
Substantive editing (sometimes called structural or content editing) looks not only at the fine details of a document, but also at the big picture to achieve the greatest impact, clarity, and readability. The substantive edit will look for variety in sentence structure, check to see that conclusions are supported, and review the organization of the document to ensure that there is consistency and flow, that sections lead logically from one another, that the right amount of information is presented, and that the document's structure, content, language, style, and presentation are suitable for its intended purpose and readership.
Copy editing aims to achieve accuracy, clarity, and consistency in a document. It deals primarily with spelling, grammar, punctuation, fact checking, word choice (does the selected word mean what the author intends?), other details of usage, and often formatting choices. It does not involve tailoring text to a specific audience, significant rewriting, or providing a single authorial voice.
Proofreading (also known as verification editing) involves checking that the document is ready to be published. It includes making sure that all elements of the document are included and in the proper order, all amendments have been inserted, the required style has been followed, and all spelling or punctuation errors have been deleted.
Nothing is written perfectly the first time. Fresh eyes can often see what the writer, after one or many iterations, will miss. Here are some suggestions for creating a good working relationship with your editor.
An editor's job is to enhance a document, to make it better in terms of accuracy, clarity, conciseness, correctness (e.g., grammar and spelling), consistency, readability, organization and flow, and style. The ultimate goal is to help the author better meet the needs of the intended audience.
At the same time, a good editor maintains the author's voice and style, ensuring that the writer's work says what the writer intends in the writer's own voice.
A good editor has an obsessive eye for detail, finding inconsistencies, mistakes, and oversights in not only usage, spelling, punctuation, capitalization, syntax, and grammar but also footnotes, reference citations, figure and table captions, page numbering, heading levels, and more.
A good editor provides honest feedback.
A good editor is a team player who knows that she serves the author, the reader, and the project.
A good editor brings to a document the polish and knowledge that a writer may not have, may not know how to use, or may not see the need for. In doing so, the editor will help an author turn a good document into a better one, and make a great document outstanding.
"This report, by its very length, defends itself against the risk of being read." —Winston Churchill