The purpose of this study was to determine whether students' responses to the Ullman student evaluation of teaching, the Student Evaluation of Teaching (SET) instrument, were biased by their achievement. The instrument was administered to all 325 students taking a second course in calculus with economic applications, near the end of the course; and separate evaluation ratings were obtained for the course, the teachers, and the examinations. An achievement rating (average midterm score) was also obtained for each student, and correlations between this rating and the SET ratings were investigated for each section of the class. Also, a one-way analysis of variance was run to investigate a possible relation between these ratings over the entire class. In most sections, the correlations between achievement and SET ratings were positive, but only 24 out of 48 were significant at the 5 percent level. The analysis of variance investigation revealed no further relationships. The authors conclude that the SET instrument under consideration may give unbiased evaluations for one teacher and biased evaluations for another, and, as such, is not to be recommended for general use. (MM)