This rubric is perfect for any argument or expository writing assignment. It is based on a 5-point scale and is appropriate for middle and high school level writers. It addresses the six traits of writing: content, organization, voice & purpose, word choice, sentence fluency, and mechanics.
I've also included the writing conference tracking form I use with my own students. I have found that it is really helpful to track writing progress using each individual trait scores as it helps identify students' strengths and weaknesses with the traits of writing.
The forms are included in both color (for display) or black and white (to make student copies). Enjoy!