Everyday at PCMI, we're doing an hour-ish of reflecting on practice. Today, we talked about productive discussion in the classroom and watched a video of Cathy Humphries teaching a 7th grade class about dividing fractions. We spent the whole time watching, re-watching, reading the transcript, discussing and even arguing (with evidence) how "good" the class conversation was. After all that, they showed us a rubric to help us discuss this in our future conversations, and I thought it was really awesome.
The rubric is from an article in the November 2007 issue of Mathematics Teacher called "Let's Talk: Promoting Mathematical Discourse in the Classroom." Enjoy! I'm blogging for speed rather than depth, but I think this alone could be food for months of study.