In other words, a group project is a cooperative, rather than a competitive, learning experience . The process of group work is only as effective as teachers or instructors manage and guide the process. Group projects are not informal collaborative groups. Students must be aware of, and prepared for, this group process. Traditional, comparative scoring works to the detriment of teams with low-achieving members.
Evaluation based upon improvement rewards the group for an individual's progress.
We assume high achievers mentor or teach low achievers. In the process of teaching others, we can learn more about the topic. As we tutor, even simple questions from the tutee make us look at our subject matter freshly. As we explain, we gain a deeper understanding of the topic.