Research indicates that student writers tend to make changes at the level of individual words instead of the kinds of global changes more experienced writers regularly make, to re-word rather than revise. So responding to surface errors plays right into the hands of students with a penchant for tinkering and does not lead to consideration of such larger issues as purpose, focus, structure, evidence, appropriateness for audience, or voice. And Sometimes, They Evaluate. It seems only fair, then, that some of the writing a student produces be evaluated as a finished product. It's hard for writing coaches to transform themselves into umpires, but grading is easier when the grading criteria have been made explicit either at the outset of the course or at the beginning of the assignment.
Instructors differ widely on how to evaluate student papers.
Instructors need not despair. Instead, they need to be consistent. They should use the same priorities to evaluate student writing as they use in responding to drafts. Again, issues of substance should take precedence. And while it is appropriate at this stage to point to errors of grammar, mechanics, and spelling, such comments should not be allowed to overshadow what one has to say about a person's ideas.