A group project that is supposed to result in a multimedia presentation should be balanced between students with strong artistic abilities vs. students with strong verbal abilities. Laboratories should not group all of the most scientifically adept students together, but instead should have less apt students mentor others, unless stronger pairs of students are given more challenging 'extra credit' work. The purpose of the assignment should reflect the nature of the group composition. Students should learn to work with students of different abilities and temperaments, but the teacher must be mindful if the assignment is supposed to produce a final outcome for which the student's performance in the entire class will be judged, versus an assignment which is designed to build skills and can benefit from student mentorship. Extended group learning projects may not be appropriate in situations where all students need drilling in relatively complex basic skills, given that teachers will have less oversight of the process. (Examples might be students who are learning the fundamentals of calculus or the subjunctive tense in Spanish). In these instances, shorter group assignments or study groups (groups where students partner with one another to study, rather than produce a final work) may be more appropriate. Students must have a certain level of confidence and adeptness to ensure that they do not reinforce one another's mistakes and are willing to fully engage in the activity. Even for a simple lab assignment, students should have some basic understanding...

There must be enough time for the teacher to realistically oversee the activities and to provide feedback and to ensure that all students are pulling their weight. Finally, creative learning can be facilitated by group learning, but it can present certain challenges. Students with artistic ability may resent having to shape their poetry, art, or other talents to suit the needs of the group. Group activity does not allow any student to create a portfolio of his or her accomplishments over the course of a semester, as the quality of the output will likely vary with the experience of other participants in the group.
With the exception of debate or civics classes, most classes are unlikely to be able to be solely graded upon group performances, but must balance group activities with individual activities to gain a full sense of the student's ability level. However, if the teacher can achieve that balance, social learning can enhance the educational process in a meaningful fashion that is useful to the learner as well as the teacher.

References

Davis, Barbara Gross. (2001). Collaborative learning. Tools for Teaching.

Retrieved May 5, 2011 at http://teaching.berkeley.edu/bgd/collaborative.html