This paper recounts the modification of a specific communication context, teacher evaluation, to produce improved instruction and better teacher-supervisor relationships. Dissatisfied with a checklist-based evaluation system considered moribund by many, a committee of teachers, administrators, and educational professionals at Anchorage (Alaska) School District examined current evaluation systems and developed a cooperative system stressing joint goal-setting and a specified series of teacher-supervisor conferences and classroom observations. The new system's phased, three-year implementation process allowed examination of teacher-supervisor relationships and instructional innovation under three supervision modes: supervisor-controlled, cooperative, and minimal supervision. Surveys of supervisors and teachers show substantial support for the cooperative evaluation model. The Survey of Supervisory Practices Form and district-developed instruments were used to assess and contrast the three evaluation conditions. The cooperative approach proved superior, as it permitted greater experimentation with educational innovation and the adoption of more innovative practices in the classroom. Another result was improved teacher-supervisor relations, shown by more positive communications and teacher perceptions of supervisor competency. Included are 2 tables, a bibliography of 39 references, and 2 appendices illustrating the supervisor-directed and cooperative evaluation forms. (MLH)