Engaging learners in constructing multimedia artifacts provides rich opportunities for them to make their thinking visible. In this research, we demonstrate the use of the VMCAnalytic, a multimedia artifact that builds on an extensive video collection of children's mathematical reasoning. Using reliable rubrics, we coded all VMCAnalytics created in a range of classes. These rubrics focused on the quality of the students' arguments and depth of their reasoning. Analysis showed that the rubric

more »

... useful in differentiating among the different groups of students. Moreover, different metrics had different degrees of correlation, suggesting that we were identifying several different dimensions of quality.