This chapter discusses how collaborative activity can be defined (circumscribed) and evaluated (appraised) in the domain of design. Collaboration is defined by situating it with respect to collective activity, cooperation and coordination. Key characteristics of collaboration are then deepened, including the shared task focus, degrees of symmetry of action, the roles of regulation, coordination and organization, technology mediation, discursive processes with affective regulation, the productive/constructive dimensions and finally the roles of cultures and values. On this basis, a specific multidimensional approach to appraising collaboration, the Quality of Collaboration (QC) method, is described, with a discussion of methodological perspectives. The chapter concludes with a discussion of the possible combination of human and AI analyses of collaboration.