This paper describes the research process and methodology used in the American Occupational Therapy Association/American Occupational Therapy Foundation Clinical Reasoning Study. This study examined the clinical reasoning of occupational therapists through a 2-year ethnography of therapists at one hospital site. The research was innovative in several important respects. One important innovation was a combined ethnographic and action research design that involved collaboration between the research team and those therapists being studied. Therapists who were research subjects became actively involved in examining and reflecting on their own practice through group analysis of videotaped sessions with clients. One outcome of this action research component was that the study served as both a research and a staff development project.