One of the more recent challenges in university teaching and learning in the Netherlands is to include peers in order to trigger effective and efficient learning processes. Students learn from peers by studying educational materials together, as well as by assessing each other's work, especially when the assessment includes feedback on the educational products and processes. This research focuses on the contribution of peer assessment to university students' acquisition of writing skills and the finding of an optimal model of peer assessment. Peer assessment is taken to be an arrangement in which students consider the quality of their fellow students' work and in which the assessment is a formative one. The department of History of the Utrecht University in the Netherlands worked out various arrangements of formative peer assessment and implemented them in seven courses distributed over the entire curriculum. These arrangements were based on a typology of peer assessment in higher education by Topping (1998). This typology consists of a survey of variables found in reported systems of peer assessment. We arranged them into four categories: variables concerning peer assessment as a method for assessing; variables concerning the interaction of the students; variables concerning the composition of the feedback groups an variables concerning requirements and rewards. The main research questions of this study are: 1. How do students and teachers carry out peer assessment?2. What components has the peer feedback? 3. How do students communicate their feedback?4. What are students' achievements as a result of peer assessment?5. How do students and teachers value the contribution of peer assessment?6. What are the differences in results between the seven designs and how are these differences related to design features?In all, 168 students and nine teachers of the History Department of Utrecht University were involved. The arrangements were evaluated by analyzing data from questionnaires, semi-structured interviews with teachers, observations of classes, students' writing products and their written and oral peer feedback. In the presentation, we will focus on the components of the peer feedback , the interaction between students when giving oral feedback and student achievement. One of our findings is that the written peer feedback was strongly focused on evaluation, and that a combination with oral feedback is advisable. Another important result is that most students used the peer feedback for the revision and thought their revised version was better than their draft version, as a consequence of using peer feedback. Most revisions were on content and style. It might be that students need more instruction in how to assess the structure of a text and that they need more time to do this. Based on the comparison between the seven designs of peer assessment and their results, we will also present our conclusions about features of the design supporting the system of peer assessment.Topping,K. (1998). Peer assessment between students in colleges and universities. Review of Educational Research, 68, 249-276.