Purpose

The purpose of this paper is to contribute with innovative knowledge about how lesson study as a method can be used as a tool for increasing in-service teachers' professional development. More specifically, the aim is to test in what way one single lesson study cycle, where teachers' way of perceiving teacher–student interactions was tested before and after, contributes to teachers' increased understanding of relational competence. The study is a pilot preparing for an upcoming main study.

Design/methodology/approach

Participants were 19 lead teachers (swe: förstelärare) in a Swedish municipality. The study was based on a relational framework and methodological approach (Aspelin, 2017; Pianta, 1999). Data obtained through web-questionnaires and collaborative group reflections were analysed and compiled to find general patterns.

Findings

The majority of the participants (98.5%) considered their understanding of relational competence to be increased (Cohen's d 1.72) during the intervention. Additionally, there was a notable increase in participants' abilities to verbalise their understanding post-intervention.

Research limitations/implications

The lack of revised studies might have impacted the validity of this work. However, as this was a pilot study the result can be considered to fulfil the purpose.

Practical implications

The research suggests that lesson study as a method for in-service teachers as participating students can be used effectively to increase teachers' professional development.

Originality/value

The study aims to investigate how lesson study as a method can be used to develop in-service teacher learning.