Lesson study is a professional development program that combines teachers’ active engagement and observation of teachers’ lessons. During a lesson study teachers collaborate in a lesson study team. In this study, four participating research supervisors have developed, taught, evaluated and redesigned a supervision meeting with a focus on undergraduate students’ research skills. During so-called research lessons, supervisors experimented with open questioning and giving positive feedback instead of giving instruction and explanations. As a result, the participating supervisors expected their students to substantiate, argue, and consider the choices they made. We aimed to identify the impact of this lesson study approach on research supervisors’ professional
development and specifically on their pedagogical content knowledge (PCK) as most important learning outcome. Triangulation by method was applied to measure supervisors’ learning outcomes and learning activities; learning reports, videotaped lesson study meetings, and exit interviews were analyzed on indicators of change (e.g. ‘I have learned’). Coding results showed two different learning outcomes and four different learning activities. Each learning outcome, and the corresponding activities were connected to the four domains of the Interconnected Model of Professional Growth. Different pathways for each supervisor’s PCK were determined by constructing pictorial representations per supervisor. This study shows that lesson study is a promising professional
development method that can have an impact on research supervisors’ PCK. Our supervisors followed different pathways of PCK change, in which the learning
activities of considering your own practice and getting ideas from others contributed the most to these changes.