This 2-year study attempted to determine whether feedback to teachers and principals about problems and tensions existing in their schools can be effective in changing morale for (1) teachers generally, (2) vocational teachers, (3) and nonvocational teachers. Relationships between teacher morale and such factors as age, sex, teaching experience, level of education, and major field were also examined. Principals and teachers (N=3,070) in 76 randomly chosen Indiana and Oregon high schools comprised the sample for the pretest-posttest control group design. The 10-component Purdue Teacher Opinionaire was used to measure morale. Statistical analysis of data revealed significant group differences. Contrary to expectations, however, all differences favored the control group. (Noncontrolled use of the feedback may have affected the results.) Patterns for nonvocational teachers followed those of the total group, but vocational teachers responded less favorably on the teacher-load factor and more favorably on the teacher- principal rapport factor. While findings concerning the relationships between personal characteristics and morale confirm the results of earlier studies, the 10-factor breakdown introduces some new dimensions. Included are a 16-item bibliography; 17 statistical tables; 13 comparison graphs; the Purdue Teacher Opinionaire; a sample of feedback profiles; and a list of cooperating schools, principals, and superintendents. (JS)