Developmental editing and line editing are very different skillsets. Developmental editors are highly analytical. They need to be logical in order to bring CLARITY to our stories. They must have a deep understanding of STORY STRUCTURE (story arc, character arc, pacing, character development, foreshadowing, etc.) and be able to identify POV issues, under-developed or missing scenes, offer suggestions for fixing plot holes, etc. – all Big Picture stuff.
Line editors, on the other hand, are more detail-oriented. Their ultimate goal is to make your writing flow, because flow is what helps create and maintain the much-desired Suspension of Disbelief.
Instead of focusing on Story Structure, line editors focus on SENTENCE STRUCTURE. They can smooth your writing so that it flows, each sentence within itself and from one sentence to the next. They do so line-by-line, identifying anything that can trip a reader up.
Anything that breaks flow needs to be flagged - e.g. redundancies (repetition, or things that are implied or over-explained), clunky sentences, unnatural dialogue, any word choice that’s not ideal, any minor logical issues missed by the developmental editor, any filtering that adds an unwanted layer between the reader and the story, making the read less immersive.
They can help with tone and style. They make the story sound good in your reader’s head, and that’s important because we all sound out the words in our heads as we read.
A line editor’s job is to ensure a smooth read for your potential reader. It’s not just about grammar and punctuation.
To conclude:
The ultimate goal of a Line Edit is to help create and maintain Suspension of Disbelief. It can make for a smooth and enjoyable read.
The ultimate goal of a Developmental Edit is to make the story logical and understandable to the reader. It can turn a confusing or rambling story with under-developed characters into a tightly-knit and compelling story with engaging characters.
Development Edit = Major (Heart) Surgery
Line Edit = Minor (Corrective) Surgery
There is no point putting band-aids on a story that is in extremis. This is why a Development Edit should come before a Line Edit.