Concerns about pupils' underachievement have stimulated various curriculum and assessment innovations in recent years. One such innovation is the British Graded Assessments in Science Project (GASP). Research focusing on the implementation of GASP highlights issues about the process of educational change, and raises the question of whether innovators take into account lessons learned from past innovations. This paper reports on two case studies of GASP implementation, showing the degree to which teachers took on board the philosophy of the scheme. The results show that even volunteer teachers, familiar with GASP, exhibit barriers to change which are well documented in the literature. One conclusion is that those developing and supporting curriculum and assessment innovation should be informed by past experience, and find real ways of helping teachers to make the changes which are required to meet the demands of the innovation.