Our school district gives pretests and posttests every year to see student growth. Since Common Core instructors have been telling us that 70% of our instruction should be focused on argument writing, I have been tweaking this rubric for the past year and a half. I believe that it finally shows a clear value of a student's argument writing ability.
The only thing some of you might like that I have not included is a portion for counter claims. In our district, we try to help students identify claims, state claims, and create claims until the end of sixth grade; counter claims are not introduced until seventh grade. (If anyone would like me to create a rubric with a counter claim component, please message me through TPT.)
The forty points can be accumulated precisely if the student has all On-Target points plus 8 processing points.
When I use this rubric, I allow the students to see the prompt on the first day and discuss with their groups, brainstorm overnight, caucus the second day with people of like opinions, and write independently on the third day.