The words proofreading and editing are often confused as the same thing, but in fact they are quite different. Take a look at the checklist so that you’re easily able to identify which service you would need.
A simple guide to the difference between proofreading and editing
Cape Town Proofreader 
This is a pretty good list. And while I do both, I often find out after I have started to work with a client, that they don’t know the difference. There is a huge difference. Proofreading is normally done after editing, though much proofreading goes INTO editing.
You are so right…it has happened to me often. I recently ‘proofread’ a dissertation which was certainly meant for ‘editing’. What I try and do now is read a good couple of pages to identify what the service is that the client really needs.
I tend to edit as I proofread as I find it too hard to proofread if the copy doesn’t flow well. Only one or two of my clients truly appreciate that what I do is as much about quality control as it is about misspelling. Just a couple of errors I picked up in recent copy: ‘Fernando’ Marcos; and Gloria Arroyo, President ‘2001-2004’. The latter mistake would have left a six-year gap in the presidency of the Philippines. Very happy client!
Hi Trish, thanks for the comment. It is very true. You can’t really proofread without editing and often, as you say, the quality control is not understood. Thanks for popping in for a visit!