Purpose -How knowledge exchange can be used for the continuous assessment and improvement of collaborative performance of project-based organisations in construction is explored. Collaboration on construction projects must be facilitated by people alongside practice of continuous performance assessment and improvement. However, currently available assessment tools fail to explicitly define appropriate behaviours and actions due to a poor understanding of what it means for people to collaborate. On the other hand, it is established that knowledge exchange is the focus of collaborative efforts on construction projects; therefore, as most knowledge resides with people, it represents their role in collaboration.Design/methodology/approach -Through a phenomenological/interpretivist and qualitative methodology, how knowledge exchange can be used for the continuous assessment and improvement of collaborative performance in project-based organisations in construction is explored. A single case study of a UK rail strategic alliance was adopted and 6 semi-structured interviews were conducted and subsequently analysed through a thematic analysis.Findings -An assessment tool is proposed based on a set of 20 characteristics of knowledge exchange, divided into seven categories and linked to indicators of collaboration. The tool can be applied to highly collaborative projects where BIM and Lean are implemented, and project participants are collocated. By measuring their performance against the set criteria, project teams can assess which of their behaviours and actions are inappropriate, and focus their efforts on correcting them.Originality/value -Defining the abstract indicators traditionally used to assess collaboration in terms of characteristics pertinent to day-to-day communication amongst participants on collaborative projects to facilitate the continuous assessment and improvement of collaborative performance.