The mission of the PD3 program in Las Cruces is to create a mathematics community within the secondary schools of the Las Cruces Independent School District and Gadsden School District that develops and sustains a group of teacher-leaders who design and implement lesson study for their peers. Teacher-leaders begin by attending two three-week summer programs of PCMI in Park City, Utah with the goals of

Learning and doing mathematics,

Analyzing and refining classroom practice, and

Becoming resources to colleagues and the profession.

Upon returning from the summer program, the teachers continue their lesson study work, with the support from the Las Cruces Professional Development Center, New Mexico State University-MC2, and Gadsden Independent School District by designing and implementing lesson study for other teachers in the district.

The lesson study team constructs a lesson using the best thinking about how students develop understanding of mathematics. The lesson is taught in a classroom with the study team observing and focusing their observations on a specific target. The lesson is then debriefed, the data and student work analyzed, and the lesson plan revised. The next version of the lesson is taught, and the cycle of debriefing, analyzing, and revising repeats. To assist in the construction of the lesson study process, protocols are developed by the team. These are procedures embedded in the process, guiding the way teachers and observers work together when discussing complex issues.

At the end of the lesson study process, the lesson is made public and published. The publishing of the lesson may happen by sharing:

• The lesson plan itself;
• Reflections on the goals and accomplishments of the lesson study group;
• Audio and video taping of the lesson; and/or
• A large audience observation or "open house."