1986 saw a radical change in the structure of examining at 16+ when, with the introduction of the General Certificate of Secondary Education in England and Wales, an element of school-based assessment was incorporated for the first time. Both the examining groups and the teaching force had to adjust to new constraints and accommodate each other's perspectives. Teachers have had to operate with closely defined criteria which were developed by the examining groups, who also subsequently monitored their application to pupils' work. This paper examines the procedures deployed to ensure comparability of judgements between teachers, both within and between schools, and highlights some of the tensions which now exist as roles have been adapted. It is suggested that some of the conflicts of interest might have been diminished, and more effective professional relationships developed between the two bodies, had procedures been more open to public scrutiny. The examining groups have a specific responsibility to maintain standards; but by taking more account of the position of teachers and their training needs, more effective long-term solutions could be evolved. Finally, it is suggested that the experiences of GCSE may be used to develop more effective mechanisms for National Curriculum Assessment, thereby making procedures smoother for all parties involved.