Lesson study is "a collaborative professional development process that involves joint lesson planning under a common goal where teachers engage in planning, implementing, observing, and reflecting on a lesson. The focus of lesson study is on mathematics and on students." Through the experience of learning about and engaging in this process, our group of six math teachers has made amazing strides in working and planning collaboratively.

Our process started with e-mail introductions between group members and narrowing our topic to middle school mathematics. When we met at PCMI, we brainstormed a variety of topics and narrowed them to two strands, both having to do with graphs and change. By the 3rd day we had selected our goal of how change is represented graphically (our big idea) and our mathematical objective of having students understand how change can be represented graphically. "Understanding" means students can explain how graphs represent change and they can relate situations to graphs. They should also be able to create real-life scenarios for a given graph. They should be able to label the axes of graphs and understand that one graph can describe more than one situation.