This study was undertaken to examine the reliability and validity of a student-designed instrument developed to provide feedback to high school teachers on student perception of teacher performance. The Student Observation of Teachers and Teaching Techniques (StOTT) questionnaire was developed by a board of eleventh- and twelfth-grade Pennsylvania students. The questionnaire contains twenty-nine positive statements concerning a teacher's classroom behavior, with a five-point scale provided for student responses. The statements are arranqed in five subsets: Student-Teacher Relations, Grades and Testing, Materials, Teacher Personality, and Teaching Methods and Techniques. Three final questions investigate: (1) distracting personal mannerisms; (2) reasons for taking the course; and (3) feelinqs about recommending the course to others. Testing of the instrument was performed with a group of thirty-six teachers and 925 students divided into three treatment groups. Analyses of student responses and comparison of these analyses with previous research on teacher rating by students suggests that the StOTT is highly useful. Students seemed capable of making and repeating stable ratings over a period of time among the items. The subscales of the instrument make sense conceptually and in general are internally consistent. The major problem uncovered is that students of differing achievement levels will tend to rate teachers differently, with the more successful students giving higher StOTT ratings, and those who are "turned off" to school giving lower ratings. The major conclusion of the study is that, while the StOTT should not be used to evaluate or compare high school teachers, it is a valuable instrument for teachers to use in their own classrooms. (MJB)