Effectiveness of grouping students to balance skills In the past, when forming student groups in class I've always allowed the students to form their own groups, which has certainly made them happy as they tend to form around social circles. As a side note, students at my school go together as classes so they have years where they know all the other people in their class quite well.

However, I'm considering doing things differently this time. I'm thinking to actively form the groups in such a way that strong students are in groups with weak students and average students - that is, groups are balanced and there are no 'strong' or 'weak' groups. I believe I can simply randomly pick students for each group and as long as strong, normal, and weak exist in roughly equal numbers, I will naturally achieve my goals, at least for the most part.

What I'm really wondering is if anyone knows the effects of student groups being formed by teachers as opposed to being formed by students themselves when those students have a strong social connection because of traveling though university as a group.

Edit: The class size is 70 and the group size is five.

Edit(2): While the studying will be done in teams, individual members are assessed individually - social loafing will hurt the loafer the most.
I have a practical suggestion based on a course I used to attend.
It was a natural continuation of another course (which was a requirement), and the majority of the student body from the first course was proceeding to take the second course.
The only team leaders were picked by the professor, in a sense that the best students from the previous class were team leaders, and were free to form their group as they wanted.
This ensured several things:

no &quot;elite&quot; team with only the top students

the groups were formed mostly to students liking

some degree of balance was naturally present
(e.g. we grouped on purpose with 6:4 in favor of &quot;stronger&quot; students, because we were allowed to distribute the assignment grade on our own, and that way non-perfect score still meant everybody got approximately the grade they wanted which coincided mostly with their effort: non-perfect project was not a tragedy)

on the previous class, a small number of students were actually &quot;pushed&quot; to go the extra mile, do exceptionally, and provide a team leader for their social group


From the student perspective, at least, it worked pretty well. If you say the student body is not changing that much from class to class, maybe something similar could work.
The downside might be that an &quot;elite&quot; group is clearly identified, but if it is based on objective criteria, and not seemingly the random whiff of a professor, it does not seem so bad.