finding the right fit when Hiring an editor
What makes an editor competitive is usually not wholly discernible from the hourly rate, which tells you little about the quality, scope, and speed (productivity) of the editor's intervention. Asking for a fixed project price is not reliable either, as the editor is rarely completely familiar with the scope of the project at the time bids are prepared and may succumb to the temptation to cut corners if he runs out of time.
Among the other factors making up competitiveness are responsiveness, adaptability, tenacity, and a willingness to assume responsibility for moving matters to closure. These are obviously desirable qualities—as no two publication processes are alike except in being full of surprises—but they are hard to demonstrate in a cost estimate. A good proxy for them may be recommendations from leaders of a wide variety of projects.
Another factor is experience, but this is easily gauged. Experienced, knowledgeable editors reduce the load on the production staff by fixing problems rather than referring them back to you. Intelligence and depth of general and specialized knowledge are related factors. Editors who do not have a broad education can’t tell terms of art from mumbo-jumbo. No one is an expert in everything, but a good editor knows what an expert sounds like. She knows how to recognize a well-reasoned and internally consistent argument.
A last factor is the depth and range of the editor's service offering: if the editor can provide ancillary writing or page layout or graphic design services, that's good. If she is a whiz with Excel and able to fix figures, that's good, too. If she can summon other editors and supervise their work, you’re getting management services as well as editorial help.