A substantial research base indicates the value of one on one tutoring. Usually those studies involved a trained specialist or instructor providing intensive instruction to the tutees. Peer tutoring hasn't shown as strong of effects but the effects can be quite positive. In traditional school settings, we see age-mates and cross-age tutors used in instructional tasks. Again, the results can be quite beneficial for both participants.
How is peer tutoring used in your instructional practices? In which academic content or skills instruction do you have a peer tutoring activity?