This review of 12 survey research studies on teacher supervision completed between 1941 and 1969 attempts to identify and interpret critical factors in supervisory performance, while also suggesting specific components of these factors. The research findings reported indicate at least three required areas of competence for effective supervisory performance. These areas include human relations, technical competence, and managerial ability. It is suggested that factor analytic studies of supervisory behavior may help to identify conceptual and performance dimensions of supervision, which can then provide the basis for the construction of sound programs of supervisory preparation. (Author/RT)