The need for collaboration in health and social welfare is well documented internationally. It is related to the improvement of services for the users, particularly target groups with multiple problems. However, there is still insufficient knowledge of the complex area of collaboration, and the interprofessional literature highlights the need to develop adequate research approaches for exploring collaboration between organizations, professionals and service users. This paper proposes a conceptual framework based on interorganizational and interprofessional research, with focus on the concepts of integration and collaboration. Furthermore, the paper suggests how two measurement instruments can be combined and adapted to the welfare context in order to explore collaboration between organizations, professionals and service users, thereby contributing to knowledge development and policy improvement. Issues concerning reliability, validity and design alternatives, as well as the importance of management, clinical implications and service user involvement in future research, are discussed.