Saying No to Self-Selection
You can count on some student complaining if you don’t let them choose their own teams. YOU MUST SAY NO.
The literature on longer term team performance is very, very clear – teacher-created, criterion-based team formation leads to better team performance. Get your words ready to respond eloquently to student push-back.
You can ask student to read
Brickell, J.L., Porter, D.B., Reynolds, M.F., Cosgrove, R.D., (1994) Assigning Students to Groups for Engineering Design Projects: A Comparison of Five Methods. Journal of Engineering Education, 7:259-262
Then ask them to write a short critique of why the paper is wrong. You tell students if you accept their argument, you will allow them to self-select. No student has ever taken me up on it.
Another way I have heard to respond is to tell a story. You are is a team with boyfriend and girlfriend, they break up mid-semester, do you want to be in that team? This story makes one of the dangers of self-selection very concrete for the students.