Lesson study in teacher education: Learning from a challenging case

•We examine one group of student teachers that struggled with implementing lesson study.•Four indicators of a challenging case emerged from analysis of empirical data.•Student teachers had little focus on observing pupils' learning.•Individual work on tasks prohibited observations of pupils' learning.•Analysis of a challenging case can inform future implementations of lesson study in teacher education.

Whereas most studies of lesson study in teacher education seem to report on success stories, this article investigates a challenging case. From an implementation of lesson study in Norwegian teacher education, we analyse data from a mathematics group that struggled with implementation. Analysis of data from group interviews, mentoring sessions and teaching the research lesson indicates that several crucial aspects of lesson study were missing. The student teachers did not formulate a research question for their research lesson, they did not focus on observing pupil learning, and their lesson was not organised to make pupil learning visible.