Composition is the creative part of writing. It’s true that outlining and paragraph structure have to be learned, but the art of composing a piece of writing can’t be taught. Ideas come from the part of the brain where imagination dwells. Strong readers do well here (hmmm, future article on Reading and Writing coming), but this part of writing is unrelated to grammar. Think of composing a piece of writing as painting a picture. The author is putting personal ideas down on paper, trying to communicate a feeling, a reaction, some sort of emotion. There is no emotion in grammar.
Grammar is often seen as the necessary evil of writing. Spelling, grammar, and punctuation go together. Without this trio, the writing is incomprehensible, and the teacher can’t tell what the student is trying to say. I’ve always told my students that writing is like talking on paper. If I can’t read it, you’re mumbling and I can’t understand you. English is such a crazy language that every rule seems to have more exceptions than examples. Grammar (I’m including spelling and punctuation here) must be explicitly taught so that students can effectively communicate. I’ve never understood why the general public loves to point fingers at misspelled signage yet doesn’t understand the need for teaching grammar.
So composition is more of a right-brain activity and grammar more of a left-brain one. Both are necessary, both need to be practiced, but each deserves a separate grade. Lumping grammar and writing in the same grading category is like scoring apples and oranges on the same fruit rubric. Students should be free to excel at one or the other without having them averaged together.