Why the limit falls where it does
The difference follows from what each level of work does. Copyediting covers spelling, grammar, usage, and punctuation, checking cross-references, and preparing style sheets. Line editors work at the sentence or paragraph level, correcting errors while concentrating on improving the language and style of the text.2 Both operate on the page in front of them, so a page is a fair specimen.
Developmental editors deal with content, organization, and genre considerations.2 None of those is visible in five pages, because organization is a property of the whole. A developmental sample can show how an editor writes a query and how they explain a judgment. It cannot show whether their judgment about a book is any good, because the book was not read.
What a sample does show
Four things are visible in a good sample, and each is worth reading for. None of them requires knowing the subject of the manuscript.
The first is scope discipline, which means doing the level of work that was ordered and no other. An editor asked for a copyedit who rewrites for style has answered a different question, and an author who accepts that sample is buying a service they did not order.
The second is how queries are written. Editors Canada's standards ask that queries, memos, and author letters be clear, tactful, succinct, and actionable.3 A sample full of changes and empty of queries is a sample from an editor who resolves rather than asks, and on some manuscripts that is the wrong instinct.
The third is voice. The standards ask that changes be made while maintaining a consistent voice, tone, and register without altering the intended meaning.3 Reading a marked-up page aloud usually settles whether that happened.
The fourth is what an author can learn about their own habits. A sample that flags the same construction eleven times has found a pattern rather than eleven errors.
What to send, and what not to
The page an author is proudest of is the wrong page. So is the worst one.
A representative passage from the middle of the manuscript tells an editor more than either, because a sample is also an estimate. A figure produced from an unrepresentative sample is an extrapolation from an unrepresentative sample, and later chapters written under different conditions can be denser than the opening.
Sending the same passage to more than one editor is what makes the responses comparable. Sending different passages produces four samples that cannot be read against each other.
The commercial questions around a sample
Practice varies on whether a sample is free, and no professional body sets that. Writer Beware records the surrounding warning signs instead. An editor who will not give a firm price, or who will not specify what the fees cover, or who will not say who will be doing the work, is one to move on from. A demand for full payment upfront is a warning sign. A reputable editor should have no difficulty supplying a resume, references, and a disclosure of fees.4
Writer Beware also suggests asking to see a sample critique or assessment, while noting that not all editors will provide one.4 The EFA's guide places references alongside evidence of comparable work rather than in place of it, and suggests asking what other work an editor has done on similar books or projects.1
None of those checks costs anything, and together they answer the question a sample cannot: whether this editor has done this kind of work before.
What EditFast does
We provide a sample edit on request and quote on the whole document rather than on the sample, so the figure does not depend on which pages an author happened to choose. The sample shows the level of work being quoted. Estimates are free and carry no obligation.
Everything a client sends is treated in confidence, including the sample, the manuscript, and any correspondence about either. Nothing sent for a sample is kept or used for anything else.
An author who reads three samples and cannot tell them apart has learned something useful. It usually means all three editors were quoting the same level of work, and the decision belongs to the other four questions a quotation should answer.