I have used the Small Group Points Sheet for several years with great success. It works much like a rubric, allowing me to clearly state my expectations ahead of time. It also provides a sort of checklist for the student.
You could print one for each student or use it to keep track of an entire group's progress. I print it double-sided and collect points until both sides have been filled. Since I see my small groups at least every other day, it usually takes about two weeks to fill. I then tally up the points for each student and calculate their participation grade.
This Small Group Points Sheet is editable, so you can change the categories to suit your needs. The example below is geared towards small reading groups and book clubs. You can pick up a copy by clicking here.
Do you have a system for small group accountability? I'd love to hear your thoughts and suggestions!