Careful pre-class planning.
Inadequate modelling, and an absence of modelling can cause groups to flounder, wasting valuable class time.
Peer response requires class time.
Whether using a five-minute pair model or a full-period group workshop model, class time is required.
Peer workshops are student centred.
Instructors need to temporarily remove themselves from the centre of attention. Students need to depend on each other for useful responses without unnecessary intervention, otherwise they will possibly resent the process.
Some students believe they work best alone.
Generally speaking, the academic world rewards independent work. Often, strong students may initially feel that the peer workshop is not going to offer them anything they couldn't do better alone. Once they participate however, they often realise the value of diverse responses to their work.
Negative attitudes.
If students or instructors have been part of badly run groups, they may have a negative attitude to peer review. Allow reservations to be voiced early in the semester so appropriate mechanisms can be established to ensure success.
Creating Effective Peer-Response Workshops. University
of Minnesota. Retrieved from the World Wide Web on 23 October, 2006:
http://writing.umn.edu/tww/responding_grading/peer_workshop.htm#potential_drawbacks