in Editing
Structural edit or line edit: which does your book need?
Polishing sentences in a chapter that may not survive the next draft is the most common way writers waste an edit.
Writers often ask for "an edit" as if there were only one kind. There are several, and the two most often confused are the structural edit and the line edit. They look at the same manuscript from very different distances, and they are most useful at different moments.
The structural edit looks at the whole
A structural edit, sometimes called a developmental or substantive edit, is concerned with the book as a built thing. Does the story begin in the right place? Does the middle hold its tension, or does it wander? Are the stakes clear, and do they rise? Does each major character want something, and does the plot put pressure on that want? In non-fiction, the same questions become: is the argument in the right order, does each chapter earn its place, and is anything essential missing?
The result is usually a long letter rather than a marked-up page. It may suggest cutting a subplot, merging two characters, moving a revelation earlier or rebuilding the ending. It rarely comments on commas, because commas are not yet the problem.
The line edit looks at the sentence
A line edit works paragraph by paragraph and sentence by sentence. The line editor asks whether each sentence says what the writer means, whether the rhythm serves the moment, whether a word is repeated three times on a page, whether a metaphor has been mixed, whether the dialogue sounds like people talking. The changes are made on the text itself, usually with tracked changes and marginal comments.
Line editing is about voice and clarity. A good line editor makes the prose sound more like the writer at their best, not more like the editor.
Order matters
The two jobs are not interchangeable, and doing them in the wrong order is expensive. Say a manuscript has a sagging middle third. If a line editor polishes those chapters first and a structural edit later recommends cutting half of them, the polishing is lost. Worse, a writer who has just seen beautifully tightened prose is understandably reluctant to throw it away, and the book suffers for that reluctance.
So the usual sequence runs from large to small: structure first, then line, then copy-editing, then proofreading. Each pass assumes the previous one is settled.
How to tell which you need
A few questions help. Have trusted readers said the book "didn't quite work" without being able to say why? Does the plot rely on a coincidence you have been hoping nobody notices? Have you rewritten the opening more than the rest of the book combined? These are structural signs.
If, on the other hand, readers follow the story happily but say the prose feels flat, over-written or uneven, and you find yourself fiddling with the same sentences, the book is probably ready for a line edit.
Some manuscripts need both, and some editors offer both. Even then, it helps to treat them as separate passes with a revision in between. A structural edit tells you what to build; a line edit helps you finish the surfaces.
If you are unsure which you need, describe the problem rather than the service, and let the editor tell you where the work lies.