I am particulary interested in peer assessment and the issue of summative assessment by students and its contribution to the formative grade. Any suggestions for further reading or a case study or 2 would be great. I can't offer any relevant case studies, although a look at Assessment and Evaluation in Higher Education for the last 10 years or so will provide a number of examples. However I'd like to comment on the first paragraph because it looks a little confused to me. Increasingly this distinction is becoming less useful as all or almost all assessment serves a summative role.
Several issues come to mind.
Incidentally, the literature on peer assessment, while by no means unanimous on the topic, does seem to indicate that, with adequate training, students' assessments are in substantial agreement with those of their teachers. Hope this helps. I am particulary interested in peer assessment and the issue of summative assessment by students and its contribution to the formative grade. Any suggestions for further reading or a case study or 2 would be great. Having been in higher education for just over three years, I am constantly amazed at the number of assessments we put our students through.