To workshop or not to workshop?

I am toying with the idea of abandoning peer workshop altogether in my comp 1 and 2 courses effective this summer. Above many items that have remained constant in my 10-plus years of teaching comp, workshop has been one of the constantest constants. If I do abandon it, understand I am not abandoning the idea of peer workshop. I have seen students profit from peer comments before, and I remain committed to the idea (perhaps in theory only) that if we aspire to do more than write in our journals solely for ourselves, we don't know what effect our words have until someone else takes them in. Abstractly at least, I still believe that's true--for someone who's committed to working with language and honing it to best possible effect.

But.

It's clear that too many of my students don't take their peers' comments seriously and perhaps, in the rush of the last minute, forget what their peers say and don't look at the feedback sheets again before turning in essays. It's also probably true that many of them don't give a fig what their peers have to say (which, perversely, I kinda cheer them for, at least their skepticism). And maybe this has to do with how the review groups work; maybe the problem is not workshop per se but who works with whom.

Trust is so hard to develop among students, but then again, trust is a double-edged sword. One kind of trust ensures that peers will review each other's work honestly and fairly, whereas another kind ensures that a group of friends will work in the same group and offer nothing but praise--if that. I wonder if there's research which attempts to measure the value of workshops in more than theoretical terms, that shows how much a student revises based on peer feedback (or other feedback, say of a writing lab or an instructor) and how much he revises out of his own convictions. And peer feedback can help *clarify* a writer's convictions, I suspect, but again, how to measure this?

Sometimes I pick group membership myself, and sometimes I let them pick--and I'm not sure which method works better. Is a relative stranger's feedback as valuable as a close friend's? I'm also starting to wonder if workshop isn't sometimes just a way of filling class time. Could those three or four days per semester be put to better advantage--more time on the research portion, more time spent on how to construct argument?

I write this and I realize I will start to address the issue this summer in my comp 2 courses. Out of time challenges more than anything else, I have taken out the workshop for all but the last essay, the research assignment. Several years ago, workshop was not part of my comp 2 course for a few semesters; then I put it back in. Now I'm taking it out again. I could foresee doing this for comp 1 as well. Is this throwing out the baby with the bathwater? Part of me also believes I owe it to stduents to at least introduce them to the idea of peer feedback, thus maybe making workshop mandatory for one or two assignments and optional for the others. (Which ones?)

If the overriding goal is improvement in student writing--more facility with language, more ease in revising toward a communicative goal--workshop should (ideally) show some influence on that. I just don't know how to measure that influence.

Obviously, more questions than answers here. Any of y'all teachers reading this who use workshop in some capacity, do you harbor similar doubts? Have you ever removed or reduced or changed the nature of your peer workshop sessions? To what effect?