But then the authors go on to state "But they bring a rich diversity of perspectives that have been shaped by their differences in class, race, culture, age and gender and that diversity enriches the work of our classrooms, making possible a shared examination of how knowledge is constructed. . . " (Kutz, Groden, Zamel 94). I think that if we make use of this diversity in the classroom when thinking ahead to assigning work, then we might possibly be able to see better writing because they will be writing about what they know and not about what we expect them to know.
Kutz, Eleanor, Groden, Suzy, and Zamel, Vivian. The Discovery of Competence: Teaching and Learning with Diverse Writers. Portsmouth, NH: Boynton/Cook , 1993.