Customer knowledge that is co-created with the customer offers mutual perceived value for the company and its customer. Many papers discuss the benefits, the process, and the success factors of customer knowledge co-creation, but only a few that discuss the unitary system. This paper promotes measurement framework that could be used to measure and to improve the productivity of the of customer knowledge co-creation in the relationship between selling firms and buying firms in projects. The contribution of this paper is measurement framework that is validated through case study on projects that involves customer in service development, and will be used in the further study on the quantification of the productivity.