The current review outlines the implications of mesosystem measurement for ecological research and models of collaborative care. Existing approaches to single and multiple mesosystem measurement emphasizing adolescent and family ecological literature are described and critiqued. Ways in which collaborative health care relationships can be assessed across mesosystem dimensions are illustrated, and relevant measurement strategies from multiple disciplines are considered. Coordinated efforts are called for to preserve the integrity of the construct and to systematically develop mesosystem measures emphasizing theory, grounded research, sound test construction, and cultural ...