The assessment of students' work has long been recognised as a key part of the learning process and yet some research suggests that despite considerable advances in recent years in terms of developing a greater variety of assessment forms, the contribution made by feedback on assessment to student learning remains a problematic area. In this paper I explore the concept of good written feedback as defined by first and third year undergraduates and academic staff in a post 1992 British university. This paper focuses on summative written feedback which I define as feedback provided on a student's assignment, after it has been submitted, which contributes to a final grade. My analysis of the data collected via semi structured interviews highlights the importance of the preconceptions of staff and students on their conception of the role and form of effective feedback. Although there are similarities in the staff and student conceptions of good written feedback there are significant areas of difference which, it is argued, can best be resolved by the adoption of more dialogic forms of feedback.