Teachers at the zone of proximal development – Collaboration promoting or hindering the development process

•Qualitative analysis makes collaborative development visible.•Trajectories of collaboration differ between differently successful teams.•Cumulating and accepting of ideas do not develop or create knowledge and practices.•Accepting as collaborative action in a group level prevents collaborative development.•Further development of ideas and questioning promote collaborative developing.

This study focuses on collaborative teacher learning during an in-service education course that supports teachers in creating knowledge and practices for teaching. The study investigates what types of activity support or hinder collaborative development within more-or-less successful teacher teams' group discussions. The findings indicate that collaboration that supports collaborative development consists of ideation, further development of ideas and raising questions. Excessive agreement appears to prevent successful collaborative development. The study suggests that in symmetrical peer-to-peer collaboration, equals are able to support creative collaboration by revising and questioning developed constructions and the developmental process itself, through the application of theoretical knowledge.