With regard to the editorial "Assembly-Line Teaching" {Oct. 31}, I believe the writer did not have adequate and accurate information about the Performance-Based Evaluation Program for teachers and administrators in the St. Louis public schools.

The view that "automatic reliance" on standardized test scores would be an inappropriate course in evaluating teachers and their supervisors is one with which I agree, for such a procedure could lead to the problems the editorial suggests. St. Louis public schools, in fact, use four factors in addition to that of student achievement-test scores to evaluate the performance of teachers. Producing learning gains in reading, language and mathematics is one of the primary missions of the public schools. In this regard, it is not only fair but reasonable to use student test results to evaluate student achievement and, thereby, the impact of instruction on learning. The other elements in performance-based evaluation depend largely on the professional observations of the principal regarding competence in the general instructional process; classroom management; interpersonal relationships with colleagues, parents and students; and the exercise of professional responsibilities.

In an urban school system such as ours, as the editorial pointed out, there are "differences and afflictions" of students that challenge the teacher. Our evaluation program is designed to take into account students' differing levels of achievement in making judgments about a teacher. In addition, unusual circumstances that would unfairly result in a negative evaluation mitigate the final rating.

It is understandable that some have expressed concerns and complaints in response to a revision of past practices, however carefully it has been developed. Adding the component of test score results in the evaluation procedure did not occur in a vacuum, nor is it accurate to say "it doesn't cost anything." This component was instituted after six years of use of the California Achievement Test to assess our students and as a final step in a three-year effort -- to which many millions of dollars were committed -- to bring about reasonable class sizes, up-to-date curricula and textbooks, adequate teaching supplies and improvements in teacher compensation.

The results of this comprehensive effort are showing. In 1981, St. Louis students in all grade levels were below the national averages in CAT scores. In 1987, students in Grades 1 to 8 were well above the national averages, and those in the high school grades showed strong advancestoward that level. There were 715 fewer dropouts from our high schools in 1986-87 than in the preceding year.

The outcomes of the evaluation process have not been cause for legitimate fear and stress. Again, the record shows that in 1986-87, only 15 teachers and five administrators were rated unsatisfactory out of a total of 4,400 certified personnel. Moreover, there have been no discharges of those so rated; they were placed on probation, with special support and counseling to help them improve their performance. The superior teaching methods practiced by the great majority of our teachers are becoming the standard for all of them.

JEROME B. JONES Superintendent of St. Louis Public Schools St. Louis