Lewis et al. (2009) propose a theoretical model for the way in which Lesson
Study produces instructional improvement. The model proposes that not only
does Lesson Study make various types of knowledge more visible (see earlier
quote), and improve resources available to teachers, but that “lesson study
enables teachers to strengthen professional community, and to build the norms”.
They add that, “these might include norms of inquiry and accountability and
shared language and frameworks for analysis of practice”