Assessment can be conducted in various ways in school, and has also different purposes. In this paper, the focus is on pupil assessment during project work. The article touches on the aim of assessment that has ranking and certificating purposes, but its main focus is on assessment as a learning device. Dialogues from the classroom are used as illustrations of authentic assessment that takes place during the work processes. These dialogues show that assessment is conducted by the teacher, by the pupils of each other and the pupils of themselves. The paper ends with a discussion bringing the assessment discussion further by focusing on criteria and goals as important ingredients in the assessment processes.