I started by giving them a copy of the rubric that came in the test prep materials for a constructed response.
We read it together and made sure they understood what it meant. Then I put the students into groups and gave them sample pieces of student work that were included in the test prep material as well.
The original items had scores at the bottom along with rationale. I cut those off before I handed them out. Then I asked the students to work together to grade each of these items.
They voted as a group to rank each one, and wrote their scores and rationale on the paper.
We then discussed the rankings as a group, and I showed them the original scores. They were much harsher than our state graders! After this process, they wrote their own responses, and worked together to improve them. I really think this will help them as they take their tests next week.