This paper explores the role of teachers in national assessment in England. The Education Reform Act of 1988 introduced a national curriculum for ages 5 to 16 together with a national assessment program for students at ages 7, 11, 14, and 16. The national assessment program is a crucial accompaniment to the national curriculum as the vehicle through which standards are to be raised. There are two main assessment methods, external tests or assessment tasks and teachers' own informal assessments of pupils' attainment called Teacher Assessment. For this, teachers make an assessment of each student's level of attainment on the scale of levels in relation to the attainment targets of the core subjects. Despite official support for the role of teachers in making assessment, there has been limited support for teachers to undertake this. In this context, teachers were surveyed about teacher assessment. In 1996, 288 teachers completed questionnaires, and 77 were interviewed. In 1997, 212 questionnaires were returned from teachers, and 216 from headteachers, and interviews were conducted with a teacher and the headteacher from 20 schools. Both studies made it clear that teachers think assessment is an essential process that has a direct impact on students' learning and their teaching. However, teachers still find the mechanisms, such as record keeping or standardization, time consuming. The studies also indicate that teachers use a variety of approaches in making their Teacher Assessment judgments, and that the assessment process would benefit from additional training for more standard approaches. (Contains 4 tables and 20 references.) (SLD)