Date of Award


Degree Type


Degree Name




First Advisor

Stanley, Darren


complexity theory, lesson study, professional learning




This research adds to the existing knowledge about using the professional learning practice of Lesson Study as a way to build pedagogical knowledge and improve teaching with in-service teachers. It has shown that Lesson Study addresses the key elements of effective professional development as described in the literature and, when viewed through a complexity theory lens, makes use of some of the key characteristics of complex systems. The research followed a team of math teachers through a modified Lesson Study, where they created a lesson, taught it, observed student learning, and debriefed the experience. The goals of the research were to understand the impact learning about instructional practice had on teachers in the study, to learn which features of the Lesson Study design supported professional learning, and to learn how teachers felt their participation in the Lesson Study impacted their students’ learning and achievement. A Design-Based Research methodology was drawn upon to gather evidence of teacher learning. Through pre-and post-surveys, interviews, observations, and artifacts, evidence was collected to study the impact of Lesson Study on the participants. Results showed teachers improved their understanding and use of strategies to have greater influence on student learning in four dimensions of mathematical reform (i.e., opportunity to learn, student confidence, student-to-student interaction, and teachers’ conceptions of mathematics). Teachers in the project reported that lesson planning and the debrief and discussion phase created the strongest opportunities for teacher learning. An efficacy survey showed that teachers improved their confidence in engaging students and improving academic performance. One of the greatest benefits of the Lesson Study, reported by participants, was the opportunity to collaborate and make curriculum connections within and between elementary and secondary school settings. Teachers also reported adopting the Lesson Study process for future professional learning time. Three recommendations that come from the research of this thesis are offered: establish a clear learning goal for teachers involved in Lesson Study based on a student need, use student data to measure success, and pay attention to the characteristics of complex systems and the elements of effective professional learning to create effective conditions for teacher learning.