Patrick Hartwell's "Grammar, Grammar, and The Teaching of Grammar" is a must-read for teachers who teach writing. Hartwell challenges the typical grammar discussion---mostly one in which one side claims that teaching traditional grammar helps students write, while the other claims that there is no research that demonstrates that teaching traditional grammar helps students write better.
It is worth noting at the outset that both sides in this dispute-the grammarians and the anti-grammarians-articulate the issue in the same positivistic terms:what does experimental research tell us about the value of teaching formal grammar
Hartwell elucidates a model for thinking about grammar, one in which there are five types or grammar, which he defines in this important piece. In effect, Hartwell's model forces us to think about what we mean when we say, "grammar."