After re-reading, my potential project appears to be part-explanatory (Does extended online role-play cause improvement in particpation / linguistic ability?) and part-emancipatory (extending abilities of learners; enriching their experience). One more than the other? Hmmm... I *feel* that there is more explanation than emancipation going on here.

Is the learning to be measured or the participation evaluated, though?? This question (and its answer) would determine perhaps whether a fixed or flexible design is warranted.