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Tuesday, November 9, 2010

Using Video to Assess "Explaining" in Math

Yesterday, I read a blog post by David Cox. He used a flipcam to videotape some of his students explaining a mathematical concept. As I watched the video a light went off in my head. One of the outcomes that is in the curriculum for my Math 10 C class is "Explain your strategy for factoring a trinomial". I could try to have the students write out an explanation but having them videotape their explanation would be even better.

So, today I took my Kodak zi8 into my class and had my students videotape each other as they explained how to factor a trinomial. What an awesome experience!!! I was able to watch every single one of my students factor a trinomial and explain it. I gained a lot of insight into the skills and the abilities of my students. Way more than just walking around the class and observing.

I just finished watching every single video and grading it using the following rubric.

This was such a success that I will definitely use it again. Video is a very powerful way to assess your students. I would suggest you give it a try. Once you do I do not think you will disagree with me.

Here is one of the videos of one of my students.


  1. Really appreciate you sharing the video and rubric. I like that the video is short. It's hard to watch/assess many student videos if they are longer and this seems like such a rich insight into what & how the students are thinking.

    I'd love to see a follow-up vid where the kids explain: "Why does the 'box method' work?" ;-)

  2. Thanks Terry. This is very neat.

    I would love to hear what the students thought about this activity. A reflective piece offered by the students could be part of the next time you use this. You could have them answer a question such as,

    In this process of filming your explanation what did you learn about your own approach to understanding the concept?

    The reflective piece helps students on the path to becoming independent, self-directed learners?